CN102132147A

CN102132147A - Defect detecting apparatus, defect detecting method, defect detecting program, and computer-readable recording medium in which that program has been recorded

Info

Publication number: CN102132147A
Application number: CN2009801341316A
Authority: CN
Inventors: 中西秀信
Original assignee: Sharp Corp
Current assignee: Sharp Corp
Priority date: 2008-08-26
Filing date: 2009-08-26
Publication date: 2011-07-20
Anticipated expiration: 2029-08-26
Also published as: CN102132147B; JP2010054247A; JP4528850B2; WO2010024303A1

Abstract

A defect detecting apparatus (1) comprises a first difference calculating circuit (23a) that calculates the difference between the brightness value (P0) of a to-be-examined pixel and each of the brightness values (P1-P8) of a plurality of to-be-compared pixels included in a to-be-compared pixel group; a second difference calculating circuit (23b) that calculates the difference between the brightness value (P0) of the to-be-examined pixel and each of the brightness values (P1'-P8') of a plurality of to-be-compared pixels included in a to-be-compared pixel group; a comparing/selecting circuit (24) that selects, as a defect detection index, one of the calculated differences the absolute value of which is the smallest of the absolute values of the calculated differences; and a defect determining unit (13) that compares the defect detection index selected by the comparing/selecting circuit (24) with a predetermined threshold value in magnitude to determine whether a defect exists at a position corresponding to the to-be-examined pixel of the to-be-examined object. In this way, the occurrence of pseudo defects can be suppressed and the defect detection can be performed with high precision.

Description

Defect detecting device, defect inspection method, defects detection program and record the recording medium of the embodied on computer readable of this program

Technical field

The present invention relates to defect detecting device etc., above-mentioned defect detecting device based on to check the brightness value that is examined pixel that comprised in the image that object takes, with the deviation of the brightness value of comparison other pixel, detect the defective of above-mentioned inspection object, above-mentioned comparison other pixel packets is contained in the above-mentioned image, becomes and the above-mentioned object that is examined pixel comparison brightness value.

Background technology

(Liquid Crystal Display: LCD) (PlasmaDisplayPanel: plasma display) (Electro Luminescence: electroluminescence) display device, liquid crystal projection apparatus etc. use the main bad defective of dull and stereotyped display device to LCD, can list line defect and point defect for display device, EL for display device, PDP.Point defect is bad caused by each pixel itself of display device, and line defect is bad etc. caused by the short circuit of adjacent signal wire, loose contact, driver element.

Under the situation that line defect and point defect to above-mentioned display device detect, use following detection method widely: promptly, take becoming the display device of checking object, the image of taking gained is resolved, thereby whether detect the position of defectiveness, defective.According to this method, owing to can make the defect inspection robotization, therefore, can reduce the needed time of defect inspection, and can cut down the needed labour cost of defect inspection, reduce the manufacturing cost of display device.

Thus, have very big advantage owing to resolve the method that detects defective by the image of the device that becomes the inspection object being taken gained, therefore, this inspection method also can be applicable to the situation beyond the display device.For example, utilize above-mentioned inspection method that the bad of imaging apparatus of camera head detected.In recent years, the resolution along with camera head improves the easy condition of poor that imaging apparatuss such as CCD take place of existence rapidly.Therefore, can use above-mentioned inspection method.In addition, also above-mentioned inspection method can be applied in the inspection to circuit such as IC.

Yet, when coming that with above-mentioned inspection method display device carried out defects detection, utilize camera heads such as camera that the output table of display device is taken.Yet in recent years, because the size of the output table of display device is fast-developing towards maximizing, therefore following parameter also constantly increases: promptly, and the aberration of the lens of camera head; And the distance of the central authorities of the lens of camera head and output table, poor with the distance of the end of the lens of camera head and output table.

Thus, obtain sometimes with hypograph: promptly, near the part of taking the central authorities to output table, and to the end near produce distortion between the part of taking.In addition, in the image that output table is taken, near the brightness value in the end light and shade lower than near the brightness value the central portion of output table also can take place change.And, be to use in display device under the situation of LCD display device of transmissive type liquid crystal panel, also can take place because of disposing the brightness irregularities that a plurality of backlights cause.Therefore, carry out binary conversion treatment at the image that for example obtains and detect under the situation of defective, exist change to cause the result problem of unstable because of the brightness value between pixel to checking object to take.

Based on Figure 16, illustrate that light and shade changes and brightness irregularities herein.Figure 16 illustrates that light and shade changes and the figure of the influence of the image that brightness irregularities obtains for output table is taken.In the figure, show the output table of display device is taken and the position on the image that obtains and the relation of brightness value.Xp is the axle of the position of expression horizontal direction (left and right directions of Figure 16), and yp is the axle of the position of expression vertical direction (above-below direction of Figure 16).In addition, x1 and y1 are the axles of expression brightness value.

In addition, Ax represents the distribution of the brightness value on the horizontal direction, and Bx is illustrated in the distribution than the brightness value on the horizontal direction in the image of Ax dark (brightness value is low), and Cx is illustrated in the distribution of the brightness value on the horizontal direction under the situation of illumination unevenness.In addition, Ay represents the distribution of the brightness value on the vertical direction, and By is illustrated in the distribution than the brightness value on the vertical direction in the image of Ay dark (brightness value is low).

In addition, no matter be when showing bright image, or when showing darker image, all will be on display device brightness value during display image to be set on whole output table be uniform.Thus, become under the uniform situation brightness value being set at the brightness value on the whole output table, light and shade changes or brightness irregularities if do not take place, and then output table is taken and the brightness value of the pixel that comprised in the image that obtains can form uniform brightness value.

Yet, as shown in figure 16,, can observe near the central portion of image and near the brightness value the end there are differences for the distribution Ax and the distribution Ay of the distribution Bx of darker image and distribution By and brighter image.In addition, for the distribution Cx under the situation that has illumination unevenness, irregular variation takes place according to the difference of the position on the horizontal direction in brightness value.

Thus, become evenly, but taking place that light and shade changes, during brightness irregularities, in brightness value, producing difference according to the different parts of output table even the brightness value of entire image display surface set.Therefore, state in the use under the situation of the display defect (for example line defect, point defect etc.) that image detects display device, need carry out light and shade and change and proofread and correct etc.

For example, under the situation of the point defect that detects the LCD display device, all use all the time and carry out the method that light and shade variation correction detects defective.In the method, predetermined display pattern is presented on the LCD display device of checking object, utilizes camera head that shown pattern is taken, to carrying out light and shade variation correction by taking the image that obtains.Then, in the image after light and shade is proofreaied and correct, the location detection that will become the above brightness value of predetermined threshold value is a fleck defect, and the location detection that will become the following brightness value of predetermined threshold value is a black spot defect.

As mentioned above, at the image that obtains based on picture display face is taken, next, utilize light and shade to change and proofread and correct the influence that reduces light and shade variation, brightness irregularities, thereby can correctly detect defective checking that object carries out under the situation of defects detection.Yet, in the method, under the larger-size situation of picture display face, need to use the smoothing wave filter of big molded dimension to carry out light and shade variation correction, therefore, there is elongated problem of processing time.

In addition, in following patent documentation 1, also use the picture display face of display device is taken and the image that obtains comes the check point defective.Particularly, generate following difference image in patent documentation 1, this difference image is to show that white bright lamp display pattern is taken and the image that obtains, take with the shiny black degree display pattern of demonstration and the difference image of the image that obtains.Then, in the difference image that is generated, it is fleck defect that the brightness more than the predetermined threshold value is detected, and the brightness below the predetermined threshold value is detected be black spot defect.

Herein, shown in patent documentation 1, be that the picture display face under the state that shows different display patterns is taken, use the difference of thus obtained image to carry out defects detection, in this case, existence needs more shooting time, elongated problem of processing time.In addition, although alleviate the light and shade variable quantity, be not complete obiteration, even the therefore technology of patent documentation 1 in order to improve accuracy of detection, also still needs to carry out light and shade and changes and proofread and correct because light and shade changes by obtaining difference.And under the situation of carrying out light and shade variation correction, the processing time is elongated certainly.

The for example following light and shade of carrying out like that changes correction.That is, in advance the image of (not having defective) inspection objects of a plurality of certified products is sampled, calculate and average brightness value by a plurality of images corresponding pixel of this sampling acquisition.Then, generate, utilize the smoothing wave filter that this image is carried out filtering, be used to carry out light and shade and change the benchmark image of proofreading and correct thereby generate with the average brightness value that calculates image as the brightness value of each pixel.The difference of the image that obtain this benchmark image, obtains with the inspection object of not knowing whether to exist defective is taken, thus can eliminate the influence that light and shade changes and whether correctly detect defectiveness.

Herein, above-mentioned light and shade changes the prerequisite of proofreading and correct and is, the shooting condition of shooting condition when taking benchmark image and the shooting when checking is consistent.Yet, to carry out defect inspection to a plurality of inspection objects usually, because of the variation of timeliness all the year round of backlight, exterior lighting etc., the maintenance of measurement mechanism etc., check that the photography conditions of object is changing all the time.

Therefore,, need upgrade benchmark image termly, make the shooting condition of benchmark image approaching as much as possible with the shooting condition of the image of checking usefulness in order to keep the precision of detection.Thereby, need termly the inspection object of certified products to be sampled, upgrade the database of benchmark image.

That is, in above-mentioned existing defect detecting method, then can improve the precision of defects detection if increase the defect inspection time, but if will when keeping the precision of defects detection, shorten the needed time of defects detection, then very difficult.Because it is short more good more that defect inspection is asked when needed, the precision of defect inspection is high more good more, therefore, can keep the precision of defect inspection below having proposed, can shorten the needed time method of defect inspection again.

Known have a following method: promptly, for example, the inspection object that comprises multiple repeat patterns for the display part of CCD, display device, IC etc., using the image of this inspection object being taken and obtaining to detect under the situation of defective of this inspection object, by the brightness value of adjacent pixels in the movement images, thereby carry out the detection of defective.Particularly, in the method, based on the brightness value that is examined pixel with and this difference of brightness value that is examined the pixel adjacent pixels whether in predetermined scope, this is examined pixel, and whether defectiveness is judged.According to this method,, therefore, can obtain the defective locations of checking object accurately owing to only whether just detect in each pixel defectiveness to checking that object is once taken.

Herein, according to above method, be the position that does not have defective of checking object is taken and under the situation of the pixel that generates, can normally to be carried out defects detection at neighbor.Yet, if neighbor is that the rejected region of checking object is taken and under the situation of the image that generates, can not be judged normally.That is, produce with normal pixel detection as defect pixel, be the problem of so-called false defect.Particularly check under the situation that contains line defect in the object easy peripheral part generation false defect in line defect.

In order to suppress the generation of this false defect, can use following method (following patent documentation 2): promptly, for example calculate the difference that is examined pixel and a plurality of neighbor (up and down,, these eight pixels of diagonal angle) respectively, the difference value that calculates is sorted according to size order, use the difference value that reaches predefined procedure.

In addition, can also use following method (following patent documentation 3): promptly, the brightness value that clips two adjacent neighboring pixels of being examined pixel (up and down,, this three class of diagonal angle) is compared computing, with the result of comparison operation be judged as the brightness value of brightness value two neighboring pixels about equally mean value, compare with the brightness value that is examined pixel, thereby judge that this is examined whether defectiveness of pixel.

And, respectively to the mean value of the brightness that clips two adjacent neighboring pixels of being examined pixel (up and down,, diagonal angle these three kinds), calculate with the difference that is examined the brightness value of pixel, from three difference values that obtain by calculating, select a difference value, thereby also can suppress the generation of false defect.Below, based on Figure 17, this method is described.

Figure 17 illustrates following decision method: promptly, by 3 groups of pixels that are examined pixel P0 and select from neighboring pixel P1～P8 are compared computing, thereby judge and be examined whether defectiveness of pixel P0.In illustrated embodiment, based on the position relation that is examined pixel P0 and neighboring pixel P1～P8 shown in the left side of this figure, 200 pairs of the defect detecting devices shown in this figure right side are examined pixel P0, and whether defectiveness is judged.As shown in the figure, defect detecting device 200 comprises the 201a～201c of comparison operation portion, selection portion 202, reaches determining defects portion 203.

The 201a of comparison operation portion compares computing 1, this comparison operation 1 be obtain be examined pixel P0, with to be examined pixel P0 is positioned at the brightness value of the neighboring pixel P4 of horizontal direction and P5 as the center mean value poor.In addition, the 201b of comparison operation portion compares computing 2, this comparison operation 2 be obtain be examined pixel P0, be positioned at poor to the mean value of the brightness value of the neighboring pixel P1 of angular direction and P8 as the center to be examined pixel P0.Then, the 201c of comparison operation portion compares computing 3, this comparison operation 3 be obtain be examined pixel P0, with to be examined pixel P0 is positioned at the brightness value of the neighboring pixel P2 of vertical direction and P7 as the center mean value poor.The comparison operation result of the 201a～201c of comparison operation portion is sent to selection portion 202.

Under the situation that the inspection object that does not have defective is taken, suppose that the brightness value of P0～P8 in theory all becomes identical value herein.Thereby if check in the object defective does not take place, then in theory, the brightness value of P0～P8 all becomes identical value (below, be called normal value), and the comparison operation result of the 201a～201c of comparison operation portion becomes 0.

In addition, in the image that reality obtains checking object to take, the on all four situation of brightness value is very rare.Therefore, even do not take place under the situation of defective in the inspection object, it is also very rare that the comparison operation result becomes zero situation.Therefore, in fact, be under 0 the situation of value in the predetermined scope in the comparison operation result, take the comparison operation result as to be 0.That is, becoming value about equally, above-mentioned comparison operation result respectively at the brightness value of P0～P8 roughly becomes under 0 the situation, then thinks with the above-mentioned corresponding position of pixel that is examined defective not to take place what check object.

On the other hand, if in checking object defective takes place, then the brightness value of P0～P8 becomes the value different with normal value.For example, check object only be examined the corresponding position of pixel P0 and take place under the situation of defective, the brightness value of neighboring pixel P1～P8 becomes normal value, only being examined pixel P0 becomes the brightness value different with normal value.In this case, the comparison operation result of the 201a～201c of comparison operation portion becomes the identical value except zero.Thereby, because of the comparison operation result is not zero, be examined pixel P0 defectiveness and can be judged to be.

As mentioned above, check object only be examined the corresponding position of pixel P0 and take place under the situation of defective, no matter use among the comparison operation result of the 201a～201c of comparison operation portion which, can both correctly judge to be examined whether defectiveness of pixel P0.

Yet, checking taking place under the situation of defective of object with the corresponding position of neighboring pixel P1～P8, the comparison operation result of the 201a～201c of comparison operation portion becomes different respectively values.Therefore, be examined whether defectiveness of pixel P0 in order correctly to judge, need from the comparison operation result of the 201a～201c of comparison operation portion, select suitable result, if comparison operation result's selection is inappropriate, although then may cause check object be examined the corresponding position of pixel P0 and do not have defective, but still be decided to be defective situation by erroneous judgement.That is, false defect takes place.

In selection portion 202, according to the preset selection rule, from the comparison operation result of the 201a～201c of comparison operation portion, select an operation result, selected operation result is sent to determining defects portion 203.Then, in determining defects portion 203, use the operation result that receives from selection portion 202, judge to be examined whether defectiveness of pixel P0.

Herein, under the situation that the such line defect of L1 for example takes place, the brightness value of P3, P5, these three neighboring pixels of P8 is different with normal value.In this case, the operation result of the comparison operation 1 of the brightness value of use P3, P5, P8 and comparison operation 2 will be subjected to the influence of L1.Thereby in this case, selection portion 202 selects not to be subjected to the comparison operation result of the 201c of comparison operation portion of the influence of L1, thereby determining defects portion 203 can correctly whether defectiveness be judged to being examined pixel P0.That is, false defect does not take place.

The prior art document

Patent documentation

Patent documentation 1: (spy opens flat 7-175442 communique (open day: July 14 nineteen ninety-five)) to Japanese publication communique

Patent documentation 2: (spy opens 2006-145232 communique (open day: on June 8th, 2006)) to Japanese publication communique

Patent documentation 3: (spy opens 2004-28836 communique (open day: on January 29th, 2004)) to Japanese publication communique

Summary of the invention

As from the comparison operation result of the 201a～201c of comparison operation portion, select not to be subjected to comparison operation result's the method for the defect influence of neighboring pixel, can consider following method: promptly, for example such shown in the patent documentation 3, two neighboring pixels that use clips in two adjacent neighboring pixels of being examined pixel (up and down, about, these three kinds at diagonal angle), brightness value is judged as about equally compare computing, select this comparison operation result.

Yet in said method, owing to use the average brightness value that clips two the adjacent neighboring pixels that are examined pixel to compare computing, therefore, the influence of the noise during shooting, demonstration noise etc. can become the unsettled reason of average brightness value.

In addition, in the example of for example Figure 17, check object with P2, P0, and the corresponding position of P7 take place under the situation of line defect, P2 and P7 the two corresponding to identical rejected region, thereby the two brightness value becomes value about equally.Therefore, might use the comparison operation result (201c of comparison operation portion carries out) who has used with corresponding P2 of rejected region and P7 and come whether defectiveness is judged to being examined pixel P0, thus, determining defects portion 203 may judge by accident be decided to be check object be examined the corresponding position of pixel P0 and defective do not take place and leaked defective.

And, as shown in figure 17, under the situation of the line defect that L2 also takes place outside the L1, because the comparison operation result of the 201a～201c of comparison operation portion is subjected to the influence of line defect L1, L2, therefore false defect may take place.

In addition, other method as the comparison operation result of the defect influence of selecting not to be subjected to neighboring pixel, also can consider following method: promptly, for example shown in the patent documentation 2, calculate the difference that is examined pixel P0 and neighboring pixel P1～P8 respectively, according to the size sequence ordering of the difference value that calculates, use the difference value that reaches predefined procedure.

Yet, in said method, the problem that exists operand to increase.That is, in said method, at first need to calculate respectively the computing of the difference that is examined pixel P0 and neighboring pixel P1～P8.Then, the computing that need sort according to the size sequence of eight operation results that calculate.Sort needed operation times according to the quantity of neighboring pixel, change with the order of employed difference value.

For example, under the situation of using eight neighboring pixels, when use difference value size is the 4th difference value, need carry out inferior comparison operation of 22 (7+6+5+4) and ordering, when use difference value size is the 5th difference value, need carry out inferior comparison operation of 25 (7+6+5+4+3) and ordering.If operand increases, then carrying out with software under the situation of computing, there is elongated problem of processing time, and carrying out with hardware under the situation of computing, there is the problem of the scale increase of treatment circuit.

As if reducing and being examined the quantity that pixel P0 carries out the neighboring pixel of calculus of differences, then can reduce the needed operand of ordering herein.Yet, reducing and be examined under the situation of quantity of neighboring pixel that pixel P0 carries out calculus of differences, the precision of operation result reduces, and may cause taking place false defect thus.

In addition, in calculating the difference be examined pixel P0 and neighboring pixel P1～P8, method respectively according to the size ordering of the difference value that calculates, difference value that use reaches predefined procedure, as shown in figure 17, under the situation of the line defect that L2 also takes place except L1, the probability that produces misinterpretation raises.Therefore, be difficult to prevent fully the generation of false defect.

The present invention finishes in view of the above problems, its purpose is to realize a kind of defect detecting device etc., this defect detecting device based on the image that obtains checking object to take, detect this inspection object defective the time, prevent the generation of false defect, and keep high defects detection precision.

In order to address the above problem, defect detecting device of the present invention is following pick-up unit: promptly, based on the brightness value that is examined pixel, brightness value with the comparison other pixel, defective to above-mentioned inspection object detects, the above-mentioned brightness value that is examined pixel is the image that obtains to checking object to take, promptly have and extract in the image of the pattern that brightness value repeats with certain cycle, above-mentioned comparison other pixel is from leaving the pixel in above-mentioned certain cycle and select at a distance of the above-mentioned pixel that is examined, the brightness value of above-mentioned comparison other pixel extracts from above-mentioned image, it is characterized in that, comprise a plurality of above-mentioned comparison other pixels, mutually different a plurality of comparison other pixel group is with above-mentioned to be examined pixel corresponding, comprise: the index computing unit, this index computing unit calculates the brightness value of each the comparison other pixel that is comprised in the above-mentioned comparison other pixel group of expression for each comparison other pixel group of above-mentioned a plurality of comparison other pixel groups, index with the size of the deviation of the above-mentioned brightness value that is examined pixel; Index in the index that index selected cell, this index selected cell calculate the These parameters computing unit, the absolute value minimum is selected as the defects detection index; And determining defects unit, this determining defects unit is based on the magnitude relationship of the selected defects detection of These parameters selected cell with index and the threshold value that is predetermined, comes being examined the corresponding position of pixel whether defectiveness is judged with above-mentioned above-mentioned inspection object.

In addition, in order to address the above problem, defect inspection method of the present invention is the performed detection method of following defect detecting device, above-mentioned defect detecting device is based on the brightness value that is examined pixel, brightness value with the comparison other pixel, defective to above-mentioned inspection object detects, the above-mentioned brightness value that is examined pixel is the image that obtains to checking object to take, promptly have and extract in the image of the pattern that brightness value repeats with certain cycle, above-mentioned comparison other pixel is from leaving the pixel in above-mentioned certain cycle and select at a distance of the above-mentioned pixel that is examined, the brightness value of above-mentioned comparison other pixel extracts from above-mentioned image, it is characterized in that, comprise a plurality of above-mentioned comparison other pixels, mutually different a plurality of comparison other pixel group is with above-mentioned to be examined pixel corresponding, comprise: the index calculation procedure, this index calculation procedure is calculated the brightness value of each the comparison other pixel that is comprised in the above-mentioned comparison other pixel group of expression for each comparison other pixel group of above-mentioned a plurality of comparison other pixel groups, index with the size of the deviation of the above-mentioned brightness value that is examined pixel; Index is selected step, and this index selects index in the index that step calculates the These parameters calculation procedure, the absolute value minimum to select as the defects detection index; And determining defects step, this determining defects step is selected the magnitude relationship of the selected defects detection of step with index and the threshold value that is predetermined based on These parameters, comes being examined the corresponding position of pixel whether defectiveness is judged with above-mentioned above-mentioned inspection object.

In addition, in said structure, it is corresponding with a plurality of comparison other pixels to be examined pixel, and above-mentioned a plurality of comparison other pixels are from leaving the pixel in above-mentioned certain cycle and choose at a distance of the above-mentioned pixel that is examined.It is being defined as under the situation of one group of comparison other pixel, it is the group who comprises many group comparison other pixels that above-mentioned comparison other group energy enough is defined as.

In addition, the defects detection index obtains as operation result, represent to be examined the index of absolute value minimum in the index of size of deviation of brightness value of the brightness value of pixel and comparison other pixel group, be used to judge check object to be examined pixel be defective or the index of certified products.

Herein, all the time, brightness value based on brightness value that is examined pixel and comparison other pixel, defective to above-mentioned inspection object detects, the above-mentioned brightness value that is examined pixel is from the image that obtains checking object to take, promptly has the image of the pattern that brightness value repeats with certain cycle and extract, above-mentioned comparison other pixel is from leaving the pixel in above-mentioned certain cycle and select at a distance of the above-mentioned pixel that is examined, and the brightness value of above-mentioned comparison other pixel extracts from above-mentioned image.

Promptly, at the image that obtains checking object to take is to have under the situation of brightness value with the image of the pattern of certain cycle repetition, if do not have defective in the above-mentioned inspection object, the brightness value that is examined pixel that then from above-mentioned image, extracts in theory with leave the brightness value of the comparison other pixel of selecting in the pixel in above-mentioned certain cycle and become identical value at a distance of the above-mentioned pixel that is examined.

Utilize above-mentioned situation, calculate the brightness value and the above-mentioned difference that is examined the brightness value of pixel of above-mentioned comparison other pixel, the difference that relatively calculates and the threshold value that is predetermined, thus can detect the defective of above-mentioned inspection object.In addition,, the corresponding position of checking object there is not the brightness value that is examined pixel or comparison other pixel under the situation of defective be called normal value herein.

More specifically, check object be examined the corresponding position of pixel, and check object all do not take place under the situation of defective with the corresponding position of comparison other pixel, the brightness value that is examined pixel and comparison other pixel all becomes normal value, in this case, above-mentioned difference becomes 0 in theory.Yet,, therefore whether judge defectiveness by comparing with threshold value because because of the influence of error etc., difference seldom can become 0 fully.That is, as long as be examined the brightness value of pixel and the brightness value of comparison other pixel is substantially can think in the same scope, just can be judged to be what check object does not have defective with being examined on the corresponding position of pixel.

In addition, check object be examined the corresponding position of pixel and defective take place, check not taking place under the situation of defective of object with the corresponding position of comparison other pixel, the brightness value that is examined pixel becomes the value that is different from normal value, and the brightness value of comparison other pixel becomes normal value.In this case, above-mentioned difference does not become zero in theory.That is, as long as be examined the brightness value of pixel and the brightness value of comparison other pixel is substantially can think in the discrepant scope, just can be judged to be check object be examined defectiveness on the corresponding position of pixel.

Yet, if checking taking place under the situation of defective of object with being examined that defective does not take place the corresponding position of pixel with the corresponding position of comparison other pixel what check object, although check object be examined the corresponding position of pixel and do not have defective, above-mentioned difference does not in theory become zero.Therefore, may judge by accident be decided to be check object be examined the corresponding position of pixel defectiveness.That is in this case, false defect may take place.

According to said structure, the index of the size of the deviation of brightness value by using each the comparison other pixel that is comprised in the expression comparison other pixel group and the above-mentioned brightness value that is examined pixel can reduce the generation of false defect.Promptly, by using the comparison other pixel group that constitutes by a plurality of comparison other pixels, even in a part of comparison other pixel that the comparison other pixel group is comprised, comprised having taken place under the situation of pixel (brightness value is the value that is different from normal value) of defective of checking object with this corresponding position of comparison other pixel, but utilize brightness value to become the comparison other pixel of normal value, thereby also can eliminate its influence.

Thus, can suppress the generation of false defect, but in the comparison other pixel of comparison other pixel group, comprise under the situation of pixel that a lot of brightness values are different from normal value, can not eliminate the influence of the brightness value different fully with normal value, therefore, false defect may take place.

Therefore, in said structure, each comparison other pixel group for a plurality of comparison other pixel groups calculates These parameters, the index of the absolute value minimum in the index that use calculates is the defects detection index, to check object whether defectiveness is judged with being examined the corresponding position of pixel.

Herein, the brightness value of each the comparison other pixel that is comprised in the index expression comparison other pixel group and be examined the size of deviation of the brightness value of pixel.Thereby according to above structure, the size of deviation of using and be examined the brightness value of pixel is minimum comparison other pixel group, comes whether defectiveness is judged.

What is called is minimum with the size of the deviation of the brightness value that is examined pixel, because therefore the deviation that means brightness value, according to said structure, can reduce to be judged to be being examined the defective possibility of pixel near zero.Thereby, according to said structure, can prevent the generation of false defect.

And, according to said structure, compare with the method for above-mentioned patent documentation 2, can carry out the judgement of defective with less operand.For example, in said structure, under the situation of using two groups of comparison other pixel groups 1 constituting by four comparison other pixels and 2, the computing of at first calculating the computing of the index that is examined pixel and comparison other pixel group 1 and calculating the index that is examined pixel and comparison other pixel group 2.Then, with the decision of the index of the absolute value minimum in the index that is calculated as the determining defects index, use this determining defects with index come to the inspection object whether defectiveness is judged with being examined the corresponding position of pixel.

Different therewith is, in the method for patent documentation 2, under the situation of using eight neighboring pixels, when using the difference value of the 4th size, carry out inferior comparison operation of 22 (7+6+5+4) and ordering, when using the difference value of the 5th size, carry out inferior comparison operation of 25 (7+6+5+4+3) and ordering, use the difference value of decision thus, to check object whether defectiveness is judged with being examined the corresponding position of pixel.Thus, in the method for patent documentation 2, because the needed operand of ordering is more, therefore compare with the structure of the invention described above, total operand significantly increases.

Herein, with regard to pixel that defective takes place and pixel that defective does not take place, the general large percentage that the pixel of defective does not take place.Therefore,, the ratio that the pixel of defective does not take place in the comparison other pixel can be reduced, the influence of defect pixel can be reduced defects detection by increasing the comparison other pixel count.

That is, according to above structure, because the increase of the operand under the situation of increase comparison other pixel count is less, therefore by increasing the accuracy of detection that the comparison other pixel count can improve defective at an easy rate.

In addition, above-mentioned defect detecting device preferably includes the comparison other pixel setup unit that above-mentioned comparison other pixel is set in the outer edge of avoiding above-mentioned image.

Its reason is, under the larger-size situation of checking object, the influence because of the aberration of camera head that this inspection object is taken etc. can deform in the outer edge of captured image.Pixel at the position that distortion will take place is set under the situation of comparison other pixel, and employed brightness value can reflect the influence of distortion in the calculating of index, and thus, the reliability of index can reduce, and therefore, is not preferred.

Therefore, according to said structure, avoid the outer edge of image and set the comparison other pixel.Thus, owing to can get rid of the influence that distortion is calculated employed brightness value to index, therefore,, also can carry out defects detection accurately even under the situation about in image, deforming.

In addition, above-mentioned defect detecting device comprises: the defective locations storage part, deposit the defectiveness position data in this defective locations storage part, the position on the corresponding above-mentioned image of the defective locations of this defective locations data representation and above-mentioned inspection object; And the comparison other pixel changes the unit, this comparison other pixel changes unit under the above-mentioned comparison other pixel position corresponding to situation represented with leaving defective data in the above-mentioned defective locations storage part in, this comparison other pixel is changed into the pixel of the position different with the position shown in the above-mentioned defective locations data.

In addition, so-called defective locations data are to represent in advance with the data of the position of the detected defective of different processing (for example well-known defect inspection method) or represent the data of the position of known defective, for example also can be with coordinate representation.

As mentioned above, whether be defects detection judge defectiveness with index to the index of the absolute value minimum in the index that calculates by use, thereby can suppress the generation of false defect.Under the comparison other pixel group comprises situation with the pixel of the corresponding position of defective locations of checking object, can think that also false defect can take place the determining defects precise decreasing because of the influence of this pixel herein.

Therefore, according to said structure, the defective locations data in advance with the corresponding position of defective locations of checking object on the presentation video is being stored in the defective locations storage part, when the represented position of stored defective locations data comprises the comparison other pixel, this comparison other pixel is changed into the represented position of defective locations data pixel in addition.

Thus, can from the comparison other pixel, get rid of and check the pixel of the corresponding position of defective locations of object.Thereby, even in the comparison other pixel group that sets, comprise under the situation with the pixel of the corresponding position of defective locations of checking object, also can keep the determining defects precision, prevent the generation of false defect reliably.

In addition, best above-mentioned determining defects unit will be in being judged to be above-mentioned inspection object during defectiveness be examined the position of pixel on above-mentioned image, as above-mentioned defective locations deposit data to the defective locations storage part, above-mentioned comparison other pixel changes the unit and uses above-mentioned determining defects unit to leave the defective locations data of above-mentioned defective locations storage part in, changes the comparison other pixel.

According to said structure, the result of determination of above-mentioned determining defects unit is used as the defective locations data, change the comparison other pixel.Thereby, according to said structure,, also need not generate the defective locations data separately even in the comparison other pixel group, comprise under the situation with the pixel of the corresponding position of defective locations of checking object, just can keep high determining defects precision, prevent the generation of false defect reliably.

In addition, above-mentioned defect detecting device preferably includes extracting position and proofreaies and correct hand, this extracting position is proofreaied and correct hand in the above-mentioned image, what different position, position was closed at the position that generates pixel taking with camera head with when checking object nearest most is examined pixel and/or comparison other pixel, this extracting position that is examined the brightness value of pixel and/or comparison other pixel is proofreaied and correct, make it near the above-mentioned position of closing on most, and make away from the above-mentioned position of closing on the position most be examined pixel and/or its correcting value of comparison other pixel is big more.

It is in addition, above-mentioned that to close on that the position also can be called most be with the position that pixel was positioned at that photographs with the nearest distance of camera head (during shooting and the position that is positioned at of the corresponding pixel in position of the nearest inspection object of camera head) when taking.

Herein, above-mentioned image is taken and is generated checking object with camera head.More specifically, above-mentioned image is to utilize the included a plurality of imaging apparatuss of camera head to be converted to electrical signal by the reflected light of checking the object reflection, and the electrical signal that each imaging apparatus is generated generates the data as the brightness value of representing each pixel.

Usually, in order to take the inspection object, use camera head with a considerable amount of imaging apparatuss.Therefore, to become the electrical signal (signal of expression brightness value) that each imaging apparatus generates be the data that pixel (imaging pixels) is uniformly-spaced arranged to image.

Yet, when utilizing the camera head that does not have a considerable amount of imaging apparatuss that the inspection object is taken, sometimes according to imaging apparatus and the distance of checking object, the pairing shooting area of each imaging apparatus difference, thus, the interval of the pixel in the image changes according to the position in this image.

More specifically, the distance of imaging apparatus and inspection object is far away more, and then the pairing shooting area of each imaging apparatus is just big more, and the pairing shooting area of each imaging apparatus is big more, and then the interval of pixel is narrow more in the image.That is, in image, away from the position (closing on the position most) to take with the nearest distance of camera head, the interval of adjacent pixels is just narrow more.

Thus, away from the pixel of the position of closing on the position most, near the offset that closes on most the position.Consequently, compare with the image that all pixels one-tenth in the image are uniformly-spaced arranged, size of images also reduces.Therefore, from image, extract under the situation of brightness value, may extract the brightness value that the position after the skew has taken place from the pixel that in fact should extract brightness value at the interval between considered pixel not.Thereby in this case, the accuracy of detection of defective also may descend.

Therefore, according to said structure, in above-mentioned image, proofread and correct being positioned at the pixel of closing on most beyond the position, make the extracting position of brightness value of this pixel near the above-mentioned position of closing on most, and make away from its correcting value of pixel of the above-mentioned position of closing on the position most big more.Thus, even under the situation that the interval of the pixel in image changes according to the position in this image, also can eliminate pixel separation skew influence and carry out defective all the time and detect.

In addition, as These parameters, the These parameters computing unit calculates: the mean value of the brightness value of each comparison other pixel that above-mentioned comparison other pixel group is comprised is poor with the brightness value that is examined pixel; Or from above-mentioned comparison other pixel group, removed the remaining comparison other pixel at least one side back in the comparison other pixel of the comparison other pixel of brightness value maximum in this comparison other pixel group or brightness value minimum brightness value mean value and be examined brightness value poor of pixel; Or the mean value of deviate in the comparison other pixel that is comprised in the above-mentioned comparison other pixel group, that removed brightness value brightness value of remaining comparison other pixel after and be examined brightness value poor of pixel than the big comparison other pixel of predetermined value; Or the brightness value of the comparison other pixel that above-mentioned comparison other pixel group comprised carried out linear interpolation and above-mentioned brightness value poor that is examined the brightness value of locations of pixels and is examined pixel obtained.

As These parameters, at the mean value of the brightness value that calculates each comparison other pixel that above-mentioned comparison other pixel group comprised be examined under the situation of difference of brightness value of pixel, can enough simple calculations calculate index.In addition, by increasing the comparison other pixel quantity that each comparison other pixel group is comprised, thereby also can improve the precision of defects detection at an easy rate.

In addition, as These parameters, calculate from above-mentioned comparison other pixel group, removed the comparison other pixel of being left at least one side back in the comparison other pixel of the comparison other pixel of brightness value maximum in this comparison other pixel group or brightness value minimum brightness value mean value and be examined under the situation of difference of brightness value of pixel, can reduce the influence of noise etc. and improve the precision of defects detection.

Its reason is, in the comparison other pixel of brightness value maximum and the comparison other pixel of brightness value minimum noise may take place, and such comparison other pixel may be corresponding with the defective of checking object.

In addition, as These parameters, the mean value of the brightness value of remaining comparison other pixel and being examined under the situation of difference of brightness value of pixel after deviate in the comparison other pixel that is comprised in calculating above-mentioned comparison other pixel group, that the removed brightness value comparison other pixel bigger than predetermined value also can reduce the influence of noise etc. and improves the precision of defects detection.

Its reason can be thought, the position that defective does not take place of general inspection object is more than the position that defective takes place, thereby under the situation of setting a plurality of comparison other pixels, the pixel that becomes normal value wants high more than the possibility of the pixel that becomes exceptional value, therefore, under the less situation of deviate, the brightness value of this pixel is that the possibility of normal value is higher, under the bigger situation of deviate, the brightness value of this pixel is that the possibility of exceptional value is higher.

Then, as These parameters, carry out linear interpolation and above-mentionedly being examined the brightness value of locations of pixels and being examined under the situation of difference of brightness value of pixel of obtaining calculating brightness value to the comparison other pixel that above-mentioned comparison other pixel group comprised, can eliminate dark variation of the system of Himdu logic and the inclination of the brightness value that causes and improve the reliability that comparison operation is handled.

Its reason is, taking place under the situation that light and shade changes, the situation that can utilize the brightness value of the pixel in the linear interpolation removal of images to change according to its position steppedly.Particularly in that being set at, the comparison other locations of pixels leaves under the situation that is examined locations of pixels, or comprise under the situation that is examined pixel and comparison other pixel in the outer edge of image, because the influence that light and shade changes becomes greatly, therefore preferably use linear interpolation.

In addition, above-mentioned defect detecting device can be by computer realization, in the case, by making computing machine each cell operation as above-mentioned defect detecting device, the recording medium that utilizes the control program of computer realization defect detecting device and record the embodied on computer readable of this control program also belongs to category of the present invention.

As mentioned above, defect detecting device of the present invention adopts following structure: promptly, comprise a plurality of above-mentioned comparison other pixels, mutually different a plurality of comparison other pixel groups and be examined pixel corresponding, comprise: the index computing unit, this index computing unit is for each comparison other pixel group of above-mentioned a plurality of comparison other pixel groups, calculate each the comparison other pixel that is comprised in the above-mentioned comparison other pixel group of expression brightness value, with the index of the size of the deviation of the above-mentioned brightness value that is examined pixel; The index selected cell, the index of the absolute value minimum in the index that this index selected cell will be calculated by the These parameters computing unit is selected as the defects detection index; And determining defects unit, this determining defects unit is based on the magnitude relationship of the selected defects detection of These parameters selected cell with index and the threshold value that is predetermined, comes being examined the corresponding position of pixel whether defectiveness is judged with above-mentioned above-mentioned inspection object.

In addition, as mentioned above, for defect inspection method of the present invention, comprise a plurality of above-mentioned comparison other pixels, mutually different a plurality of comparison other pixel groups and be examined pixel corresponding, comprise: the index calculation procedure, this index calculation procedure is for each comparison other pixel group of above-mentioned a plurality of comparison other pixel groups, calculate each the comparison other pixel that is comprised in the above-mentioned comparison other pixel group of expression brightness value, with the index of the size of the deviation of the above-mentioned brightness value that is examined pixel; Index is selected step, and this index selects the index of the absolute value minimum in the index that step will calculate by the These parameters calculation procedure to select as the defects detection index; And determining defects step, this determining defects step is selected the magnitude relationship of the selected defects detection of step with index and the threshold value that is predetermined based on These parameters, comes being examined the corresponding position of pixel whether defectiveness is judged with above-mentioned above-mentioned inspection object.

Thereby, even in the comparison other pixel, comprise under the situation of pixel that brightness value is different from normal value, also have the generation that can prevent false defect, the effect of keeping high defects detection precision.

Other purposes of the present invention, feature and advantage should fully be understood according to record as follows.In addition, value of the present invention should be known from the following explanation of reference accompanying drawing.

Description of drawings

Fig. 1 represents embodiments of the present invention, is the block diagram of the major part structure of expression defect detecting device.

Fig. 2 is the explanation relation of checking the image that object obtains with this inspections object is taken, and the image that obtains checking object to take in be examined the figure that pixel and comparison other locations of pixels concern.

Fig. 3 is the concise and to the point figure of the performed defect inspection method of the above-mentioned defect detecting device of explanation.

Fig. 4 is the block diagram of major part structure that expression comprises the check system of above-mentioned defect detecting device.

Fig. 5 is the process flow diagram of an example of the above-mentioned defects detection processing of expression.

Fig. 6 is that expression is taken display device and the distortion that generates in the image that forms, and is used to set the figure of the relation between the piece of comparison other locations of pixels.

Fig. 7 is the figure of the setting example of the comparison other locations of pixels in the bight of presentation video.

Fig. 8 be presentation video upper end, left part, right part, and the bottom in the figure of setting example of comparison other locations of pixels.

Fig. 9 is the figure of relation of the spacing of the pixel in the image that generates with this position is taken of explanation position when with the camera of TDI/ line sensor type display device being taken, on the display device.

Figure 10 represents embodiments of the present invention, is explanation and the concise and to the point figure of above-mentioned different defect inspection method.

To be explanation using each group to comprise the figure of the example of the comparison other pixel of changing into the position that does not have defective under the situation of 3 groups of comparison other pixels 1～3 of four comparison other pixels, with the comparison other pixel of defective locations to Figure 11.

Figure 12 is the block diagram of the major part structure of the expression defect detecting device of carrying out above-mentioned defect inspection method.

Figure 13 is the process flow diagram of an example of the processing of expression decision comparison other pixel.

Figure 14 represents prior art, is the figure of an example of the detection method of expression defective locations.

Figure 15 represents prior art, is the figure of an example of the detection method of expression defective locations.

Figure 16 illustrates that light and shade changes and the figure of the influence of the image that brightness irregularities obtains for picture display face is taken.

Thereby Figure 17 is explanation to be judged and to be examined the whether figure of defective decision method of pixel by 3 groups of pixels that are examined pixel and select from neighboring pixel being compared computing.

Reference numeral

1 defect detecting device

1 ' defect detecting device

12 difference value calculating parts

12 ' difference value calculating part

13 determining defects portions (determining defects unit)

20 first address control circuits (comparison other image setting unit, extracting position correcting unit)

21 view data are read in circuit

22a～22i ' impact damper

The 23a first calculus of differences circuit (index computing unit)

The 23b second calculus of differences circuit (index computing unit)

24 comparison/selection circuit (index selected cell)

27 defective locations storeies

28 select circuit (the comparison other pixel changes the unit)

Embodiment

Embodiment 1

Below, according to Fig. 1 to Fig. 9, an embodiment of the invention are described.The defect detecting device of present embodiment is for the pixel one by one of the image that obtains checking object to take, come relatively brightness value with the neighboring pixel of this pixel, thereby determine the unusual pixel (pixel) of brightness value with the brightness value that is different from normal value, thus, detect point defect, the line defect of checking object.Below, will become the object pixels whether brightness value is normally judged and be called and be examined pixel, will become and be examined the object pixels that pixel compares and be called the comparison other pixel.In addition, will be normal (with set identical) brightness value be called normal value, brightness value that will unusual (than the brightness value height of setting or low) is called exceptional value.

At the brightness value of brightness value by relatively being examined pixel and the comparison other pixel around it, judge the brightness value that is examined pixel whether under the normal situation, be examined pixel around need to exist with this and be examined the comparison other pixel that pixel has the same brightness value in theory.Thereby, for checking object, in the image that this inspection object is taken, the pixel of the brightness value identical with this pixel need appear having around each pixel.Particularly, if check that object has repeat patterns, just can satisfy this condition.

Below, be that the example of display device P describes to checking object.In the display frame of display device P,, therefore be suitable as the inspection object because rgb pixel is arranged (repeat patterns with RGB) regularly.For example, also can (Cathode Ray Tube: cathode-ray tube (CRT)) display device etc. be as checking object with LCD display device, EL display device, PDP display device, liquid crystal projection apparatus, CRT.In addition, having repeat patterns as long as check object, also can be for example IC, CCD etc.

In the image that above-mentioned inspection object is taken, the pattern that brightness value repeats with some cycles appears.Therefore, extracting from above-mentioned image under the situation of a pixel, the locational pixel of leaving above-mentioned certain cycle at a distance of this pixel has the identical brightness value of pixel that goes out with said extracted in theory.Thereby, can will be examined locational pixel that pixel leaves above-mentioned some cycles object pixel as a comparison apart.

(about being used for the image of defects detection)

Herein, at first, based on Fig. 2, illustrate the image that obtains checking object to take, and this image in be examined pixel and comparison other locations of pixels relation.Fig. 2 is the explanation relation of checking the image that object obtains with this inspections object is taken, and the image that obtains checking object to take in be examined the figure that pixel and comparison other locations of pixels concern.

In Fig. 2, rectangular quadrilateral is represented the display pixel of display device P, and foursquare quadrilateral is represented this display device P is taken and pixel (photography pixel) in the image that obtains.Display pixel has these three kinds of R, G, B, arranges with the order along continuous straight runs (left and right directions of Fig. 2) of R, G, B.Then, on vertical direction (above-below direction of Fig. 2), be arranged with the display image of same color.Form the pixel of display device P by R, G, these three display images of B.

As shown in the figure, the photography pixel is assigned 6 to the pixel (R, G, these three display pixels of B) of display device P in the horizontal direction, and a pixel to display device P is assigned 3 in vertical direction.That is, as shown in the figure, a display pixel is assigned 6 imaging pixels.Therefore, the brightness value of a display pixel is reflected in six imaging pixels that are assigned in this display pixel.In addition, for the distribution of imaging pixels,, be not limited thereto example as long as a display pixel is assigned an imaging pixels at least.

In illustrated embodiment, for the pixel of from imaging pixels, selecting that is examined, will be that at interval (cm) becomes 6 to horizontal pixel, the interval on above-below direction is vertical pixel (cn) imaging pixels object pixel as a comparison of becoming 6 position at interval at the interval on the left and right directions.

Horizontal pixel is made as 6 the reasons are as follows at interval: promptly, on left and right directions, pixel (R, G, these three display pixels of B) to display device P is assigned six imaging pixels, thereby separates the identical position of the imaging pixels of 6 positions corresponding to the display pixel of same color with respect to being examined pixel on left and right directions.

That is, in illustrated embodiment, be examined the upper right side of pixel corresponding to the R display pixel, two the comparison other pixels adjacent with the left and right directions that is examined pixel are too corresponding to the upper right side of R display pixel.Thus, be made as identical position with the display pixel that is examined the pixel same color by making the comparison other locations of pixels, thereby can whether normally judge the brightness value that is examined pixel.

In addition, as long as the comparison other locations of pixels becomes and the same position that is examined the display pixel of pixel same color.That is, in illustrated embodiment, so long as, just can become the comparison other pixel with respect to being examined pixel separates the position of 6 integral multiple on left and right directions imaging pixels.

Also identical in vertical direction, will be made as the comparison other pixel with respect to being examined the imaging pixels that pixel separates 6 positions in vertical direction respectively.In vertical direction, so long as, just become the comparison other pixel with respect to being examined the imaging pixels that pixel separates the position of 3 integral multiple in vertical direction.

Thereby, for example also can will be made as the comparison other pixel with respect to being examined the imaging pixels that pixel separates 3 positions in vertical direction.Yet, in a display pixel, take place also identical defective may take place in the display pixel adjacent under the situation of defective with this display pixel.Particularly under the situation that line defect takes place, this possibility raises.

Therefore, preferably the comparison other locations of pixels is set to and is examined the adjacent display pixel of the corresponding display pixel of the pixel pairing position of display pixel in addition.Therefore, in illustrated embodiment, will be made as the comparison other pixel with respect to being examined the imaging pixels that pixel separates 6 positions in vertical direction respectively.

(briefing of defect inspection method)

The defect detecting device of present embodiment uses in the mode that the display pixel that becomes the display device P that checks object is assigned as mentioned above like that imaging pixels and takes and the image that obtains, carries out the defects detection of above-mentioned display device P.

Based on Fig. 3, the briefing of the defect inspection method that above-mentioned defect detecting device carries out is described herein.Fig. 3 is the concise and to the point figure of the defect inspection method of explanation present embodiment.In addition, in Fig. 3, represent to be examined pixel, represent comparison other pixel 1, represent comparison other pixel 2 with P1a～P8a with P1～P8 with P0.In addition, in Fig. 3, not drawing for simplification is examined pixel between pixel and the comparison other pixel.That is, in Fig. 3, also as shown in Figure 2, be arranged with pixel being examined between pixel and the comparison other pixel.

As shown in Figure 3, comparison other pixel 1 (P1～P8) be positioned at be examined about the pixel P0, about, to the comparison other pixel on the angular direction.And (P1a～P8a) is a left side tiltedly below, and the right tiltedly comparison other pixel of below of P8 of right oblique upper, P6 of left oblique upper, P3 of right-hand, P1 of left, the P5 of below, the P4 of the top that is positioned at comparison other P2, P7 to comparison other pixel 2.

In the defect inspection method of present embodiment, object pixel 1 (P1～P8) and comparison other pixel 2 (P1a～P8a) based on the comparison, whether the brightness value that is examined pixel P0 is normally judged, thus, to whether having display defect (line defect, point defect etc.) to judge with the display pixel that is examined the corresponding position of pixel P0.

Herein, as mentioned above, if checking in the object (under this situation, being display device P) there is not defective fully, the brightness value that then is examined pixel P0 equates with the brightness value of comparison

other pixel

1 and 2, if check object be examined the corresponding position of pixel P0 defectiveness, then be examined the brightness value of pixel P0 and the brightness value generation difference of comparison other pixel 1 and 2.Thereby, can be based on the brightness value that for example is examined pixel P0 and comparison

other pixel

1,2 poor, whether the brightness value that is examined pixel P0 is normally judged.

Yet as shown in Figure 3, under the situation that line defect takes place, the brightness value of the P3 of comparison other pixel 1, P5, P8 becomes the value different with normal value.In this case, be examined pixel P0 and comparison other pixel 1 and (in the difference of the mean value of P1～P8), reflect P3, P5, P8 that the value that is different from normal value is arranged.Therefore, under the situation of using this difference value to come whether the brightness value that is examined pixel P0 is normally judged, false defect may take place.

Therefore, in above-mentioned defect inspection method, (difference of the mean value of P1～P8) is carried out computing, and (difference of the mean value of P1a～P8a) is carried out computing to being examined pixel P0 and comparison other pixel 2 to being examined pixel P0 and comparison other pixel 1.And, the absolute value of two difference being obtained by computing is compared, select the less difference value of absolute value as the difference value that is examined the judgement usefulness of pixel P0.

Then, more above-mentioned selected difference value and set threshold value (fleck defect judge with), under the situation of above-mentioned difference value greater than this threshold value, being judged to be being examined pixel P0 has fleck defect.In addition, more above-mentioned selected difference value and set threshold value (black spot defect judge with), under the situation of above-mentioned difference value less than this threshold value, being judged to be being examined pixel P0 has black spot defect.

According to said structure, select the less difference value of absolute value in two difference values as the difference value that is examined the judgement usefulness of pixel P0.Thus, use and to be judged as the lower difference value of defective possibility and to carry out whether defective judgement.Thereby, even in the comparison other pixel, comprise under the situation of pixel of the brightness value different, also can prevent the generation of false defect with normal value.

In addition, according to above structure, being examined between pixel P0 and comparison

other pixel

1 and 2 is 6 narrower intervals about the pixel of pixel～12 at interval.In above-mentioned less zone, comparing under the situation of calculation process the influence that the light and shade that the factors such as lens peculiarity, lighting condition because of camera head 2 that are subjected to hardly produce changes.That is,, do not need as existing, to utilize Filtering Processing to carry out light and shade and change correction according to said structure.In addition, be a width of cloth for the needed image of the inspection of carrying out display device P.Thereby, according to said structure, can at a high speed and carry out the detection of defective accurately.

In addition, according to said structure, do not need to use benchmark image to carry out light and shade yet and change correction.Therefore, even, also can detect defective in all-the-time stable ground causing because of factors such as lighting condition variation, device maintenances under the situation that the photography conditions of display device P changes.

And, according to above structure, with the comparison other pixel be set at be positioned at apart be examined pixel separate certain intervals, be examined the pixel of pixel same color.Thus, around being examined pixel and/or its, take place under the situation of line defect, can prevent that the most brightness value of comparison other pixel from becoming the value different with normal value.Therefore, the defects detection precision improves, and also can stably carry out defects detection.

In addition, in the example of Fig. 3, show the example that uses two groups of comparison other pixels (comparison other pixel 1 and 2), but the group number of employed comparison other pixel is many more, just can improves the precision of defects detection more.Its reason is that the group number of comparison other pixel is many more, then uses the comparison other pixel in the group that does not comprise the comparison other pixel with brightness value different with normal value to calculate difference value, uses this difference value to judge whether defective probability is high more.

(briefing of check system 100)

Then, based on Fig. 4, the briefing of the check system 100 of present embodiment is described.Fig. 4 is the block diagram of major part structure of the check system 100 of expression present embodiment.As shown in Figure 4, comprise defect detecting device 1 and camera head 2 in the check system 100, comprise image input part 10, video memory 11, difference value calculating part 12, determining defects portion (determining defects unit) 13 in the defect detecting device 1, reach display control unit 14.And, in the image pickup scope of camera head 2, disposing display device P, display device P is connected with display device drive circuit 4, and display device drive circuit 4 is connected with pattern generator 3.

Display device P is the inspection object of check system 100.Display device drive circuit 4 drives display device P based on the display pattern that pattern generator 3 generates, thereby can will be shown in display device P with the corresponding image of above-mentioned display pattern.

2 pairs of images that are shown in display device P of camera head are taken, and will output to image input part 10 by the view data that take to obtain (carry out digitizing after gray scale image).As shown in the figure, camera head 2 can be along moving with the vertical direction of the picture display face of display device P (direction of representing with arrow A) and the direction parallel with the picture display face of display device P (direction of representing with arrow B).Thus, can take in the suitable position of the size of the image pickup scope that meets camera head 2, display device P.

In addition, camera head 2 can be an area sensor, also can be line sensor, but is of a size of under the large-scale situation at display device P, based on the consideration of resolution, preferably uses TDI/ line sensor (time delay accumulation molded lines sensor).But, be under the situation of line sensor at camera head 2, the mechanism that camera head 2 is moved with respect to display device P need be set.

Image input part 10 is the interfaces that the view data that camera head 2 is obtained are taken into defect detecting device 1.The view data that camera head 2 is obtained is taken in the defect detecting device 1 by image input part 10, and the view data that is taken into is stored in the video memory 11.Can utilize wire communication that view data is sent to defect detecting device 1 from camera head 2, also can utilize the mode of radio communication to carry out, the structure of image input part 10 is that the send mode according to view data determines.

Video memory 11 is to deposit the record image data medium that is taken into by image input part 10.As long as video memory 11 is the storeies that write and read that can carry out data.In addition, in check system 100, also the defects detection result can be stored in video memory 11.In addition, also can be with the defects detection outcome record to the recording medium different with video memory 11.

Difference value calculating part 12 is read the view data that leaves in the video memory 11, based on the view data of reading, calculating becomes the difference value of the foundation that defectiveness is judged whether among the display device P, and the difference value that calculates is sent to determining defects portion 13.In addition, hereinafter will describe the computing method of difference value in detail.

The difference value that determining defects portion 13 calculates based on difference value calculating part 12 is to whether defectiveness is judged among the display device P.Particularly, determining defects portion 13 more above-mentioned difference values and the threshold value that is predetermined, thus whether judge defectiveness.Then, be judged as under the defective situation, determining defects portion 13 is stored in the position of defective in the video memory 11.

In addition, whether determining defects portion 13 based on defective result of determination, goes up shown display pattern and judges that be judged as under the situation that needs to change, indicated number control part 14 changes display pattern whether needing to change display device P.

(the detailed formation of defect detecting device 1)

Then, based on Fig. 1, illustrate in greater detail the structure of defect detecting device 1.Fig. 1 is the block diagram of the major part structure of expression defect detecting device 1, shows the details of difference value calculating part 12 and determining defects portion 13 especially.

As shown in the figure, difference value calculating part 12 comprises that first address control circuit (comparison other pixel setup unit, extracting position correcting unit) 20, view data read in circuit 21, impact damper 22a～22i ', the first calculus of differences circuit (index computing unit) 23a, the second calculus of differences circuit (index computing unit) 23b, comparison/selection circuit (index selected cell) 24, compared pixels determining positions table 25, and pixel separation decision table 26.In addition, determining defects portion 13 comprises determining defects treatment circuit 30, output buffer 31, view data write circuit 32, reaches second address control circuit 33.

First address control circuit 20 is to read in the image of circuit 21 from leave video memory 11 in view data to specify the circuit that reads in the position when difference value calculating part 12 reads in brightness value.More specifically, first address control circuit 20 position (address) of reading in of reading in position (address) and comparison other pixel that will be examined pixel sends to view data and reads in circuit 21.Thus, view data read in circuit 21 will be stored in the video memory 11, display device P is taken and the brightness value of the pixel of the position of being determined by above-mentioned address in the image that obtains reads in difference value calculating part 12.

Herein, first address control circuit 20 at first with the pixel decision of the left upper end of above-mentioned image as being examined pixel, its address is sent to view data reads in circuit 21.Yet 20 decisions of first address control circuit are examined the corresponding a plurality of comparison other locations of pixels of locations of pixels with this, its address is sent to view data read in circuit 21.In addition, hereinafter will narrate the determining method of comparison other locations of pixels.

Then, first address control circuit 20 will be examined pixel as the next one with the right adjacent pixels decision that begins most to be set as the pixel that is examined pixel, its address be sent to view data read in circuit 21.Then, the decision of first address control circuit 20 with should new decision be examined the corresponding a plurality of comparison other locations of pixels of locations of pixels, its address is sent to view data reads in circuit 21.

Repeat this processing, until being examined the right-hand member that locations of pixels arrives image, first address control circuit 20 is examined locations of pixels with the determining positions of the left end of a pixel below on the vertical direction as the next one.Repeat this processing, all become the stage that is examined pixel one by one in all pixels of image, the defects detection processing of this image finishes.In addition, specify, make all pixels of image become at least one by one to be examined pixel to get final product that the specified order that is examined pixel is not limited to above-mentioned example as long as first address control circuit 20 carries out the address.

It is following circuit that view data is read in circuit 21: promptly, indication according to first address control circuit 20, with leave in the video memory 11, display device P is taken and the brightness value of the image that obtains is read into difference value calculating part 12, output to impact damper 22a～22i and 22b '～22i '.That is, view data is read in the brightness value that circuit 21 reads in the position image that leaves in the video memory 11, that first address control circuit 20 is specified, and the brightness value that is read in is outputed to impact damper 22a～22i and 22b '～22i ' respectively.

Particularly, first address control circuit 20 will be examined position (address) and comparison other pixel the position (address) in image of pixel in image and output to view data and read in circuit 21, view data is read in circuit 21 based on this address, image from leave video memory 11 in reads in brightness value, and the brightness value that is read in is outputed to impact damper 22a～22i and 22b '～22i ' respectively.

In addition, the brightness value that will be examined pixel (P0) is read into impact damper 22a, and (brightness value of P1～P8) is read into impact damper 22b～22i, and (brightness value of P1a～P8a) is read into impact damper 22b '～22i ' with comparison other pixel 2 with comparison other pixel 1.

Herein, view data is read in circuit 21 and is carried out basically for each pixel its brightness value being stored in the action of each impact damper, but also can be once the brightness value of a plurality of pixels be transferred to impact damper.Thus, can realize the high speed of the high efficiency and the transmission speed of memory transfer.Above-mentioned processing for example also can use the DDR/DDR2 storer of widely used in recent years 64 buses to realize.

The first calculus of differences circuit 23a to leave the brightness value that is examined pixel (P0) among the impact damper 22a in, (difference of the mean value of the brightness value of P1～P8) is carried out computing, and outputs to comparison/selection circuit 24 with leaving comparison other pixel 1 among impact damper 22b～22i in.

Equally, the second calculus of differences circuit 23b to leave the brightness value that is examined pixel (P0) among the impact damper 22a in, (difference of the mean value of the brightness value of P1a～P8a) is carried out computing, and outputs to comparison/selection circuit 24 with leaving comparison other pixel 2 among impact damper 22b '～22i ' in.

The absolute value of the difference value that 24 pairs in comparison/selection circuit receives from the first calculus of differences circuit 23a, compare, that less difference value is sent to determining defects treatment circuit 30 with the absolute value of the difference value that receives from the second calculus of differences circuit 23b.Thus, use the less difference value of absolute value to carry out determining defects.

By using the less difference value of absolute value to carry out determining defects, thereby at the brightness value that because of the brightness value that is examined pixel is normal value, comparison other pixel is that exceptional value causes under the big situation of difference value change, can prevent to judge by accident that to be decided to be this brightness value that is examined pixel be exceptional value, can prevent the generation of the false defect that causes thus.

In addition, the reason of the absolute value of poor score value is herein, include display pixel in the defective of display device P and have the fleck defect of the brightness value bigger and the black spot defect that display pixel is not lighted than normal value, under the situation that fleck defect takes place and under the situation of generation black spot defect, the symbol of difference value will reverse.

Compared pixels determining positions table 25 be make be examined locations of pixels (address), with corresponding to the corresponding form of comparison other locations of pixels (address) of this position.First address control circuit 20 is after decision is examined locations of pixels, and with reference to compared pixels determining positions table 25, thereby decision is corresponding to the above-mentioned comparison other locations of pixels that is examined locations of pixels that determines.

In addition, with be examined the corresponding comparison other locations of pixels of locations of pixels and get final product (at the normal value of the brightness value of the pixel of this position, become the position of identical value in theory) with the normal value that is examined the brightness value of pixel so long as become this position that is examined the comparison other of pixel, there is no particular limitation, and the comparison other locations of pixels preferably can change according to being examined the position of pixel on image.The comparison other locations of pixels is changed according to being examined the position of pixel on image, because this is not essential processing, so this processing will be narrated hereinafter.

Pixel separation decision table 26 is the tables that are examined locations of pixels and comparison other locations of pixels that are used for proofreading and correct according to the position on the image 20 decisions of first address control circuit.By using pixel separation decision table 26, even, also can carry out defects detection accurately because of the aberration of the lens of camera head 2, distortion etc. cause the interval of pixel to produce under the different situations with the end at the central portion of image.In addition, because pixel separation decision table 26 is not defect detecting device 1 a necessary structure, therefore hereinafter will be described in detail pixel separation decision table 26.

Determining defects treatment circuit 30 uses the difference value that receives from comparison/selection circuit 24, is that normal value or exceptional value are judged to the brightness value that is examined pixel.If the brightness value that is examined pixel is a normal value, then represent being examined the corresponding position of pixel with this and not having defective of display device P, if exceptional value, that then represents display device P is examined the corresponding position of pixel defectiveness with this.

Particularly, the difference value that determining defects treatment circuit 30 relatively receives from comparison/selection circuit 24, detect with the bright spot of storage in advance and to use threshold value, if being bright spot, difference value detects with the above value of threshold value, then be judged to be being examined the corresponding position of pixel with this fleck defect is arranged of display device P, leave the decision content of this result of determination of expression in output buffer 31.

In addition, the difference value that determining defects treatment circuit 30 relatively receives from comparison/selection circuit 24, detect with the stain of storage in advance and to use threshold value, if being stain, difference value detects with the following value of threshold value, then be judged to be being examined the corresponding position of pixel with this black spot defect is arranged of display device P, leave the decision content of this result of determination of expression in output buffer 31.

In addition, determining defects treatment circuit 30 the difference value that receives from comparison/selection circuit 24 detect than bright spot little with threshold value, detect under the situation big than stain with threshold value, be judged to be being examined the corresponding position of pixel with this and not having defective of display device P, the decision content of this result of determination of expression is stored in output buffer 31.In addition, also can be so that only detect the position of black spot defect or fleck defect to output buffer 31 outputs.

The decision content that view data write circuit 32 will leave output buffer 31 in is stored in the specified address of second address control circuit 33 of video memory 11.As mentioned above, first address control circuit 20 carries out the address specifies, and all becomes and is examined pixel so that leave all pixels of the image in the video memory 11 in.Therefore, will deposit the deposit data of each decision content in video memory 11 for all pixels of image at last.

The flow process that＜defects detection is handled 〉

Then, based on Fig. 5, the flow process of the defects detection processing of being undertaken by defect detecting device 1 is described.Fig. 5 is the process flow diagram of an example of expression defects detection processing.In addition, implement before the process flow diagram of Fig. 5, the display pattern of earlier defects detection being used is shown in display device P, utilize 2 pairs of these display patterns of camera head to take, be stored in video memory 11 with taking the image that obtains by image input part 10, the process flow diagram of Fig. 5 shows processing after this.

At first, the first address control circuit 20 vertical address counter (Vcnt) that expression left in the image of video memory 11 in position (address) in vertical direction is set at 0 (S1)., as mentioned above, carry out defect inspection successively herein owing to be envisioned for from the left upper end of image, therefore, the upper end that the position becomes image of reading in that the vertical address counter is set at 0 o'clock.

Then, the first address control circuit 20 horizontal address counter (Hcnt) that expression left in the image of video memory 11 in position (address) in the horizontal direction is set at 0 (S2)., as mentioned above, carry out defect inspection successively herein owing to be envisioned for from the left upper end of image, therefore, the left end that the position becomes image that reads in that horizontal address counter is set at 0 o'clock.

That is, in S1 and S2, vertical address counter and horizontal address counter are set at 0, thereby read in the left upper end that the position becomes image.The decision of this place read in the position be examined pixel brightness value read in the position.If determined to be examined pixel brightness value read in the position, then first address control circuit 20 is with reference to compared pixels determining positions table 25, decides the position of reading in the brightness value that reads in the corresponding comparison other pixel in position of the above-mentioned brightness value that is examined pixel that determines.

Then, first address control circuit 20 brightness value that is examined pixel that will determine like that as mentioned above read in position (value of vertical address counter and horizontal address counter), and the position of reading in of the brightness value of comparison other pixel send to view data and read in circuit 21.

Receive the brightness value that is examined pixel read in the position, and the view data of reading in the position of the brightness value of comparison other pixel read in circuit 21, according to the position of reading in of the brightness value that is examined pixel that is obtained, the brightness value (P0) that will read from video memory 11 is stored in impact damper 22a.In addition, view data is read in the read in position of circuit 21 according to the brightness value of the comparison other pixel of being obtained, (P1～P8) is stored in impact damper 22b～22i (S3) to the brightness value that will read from video memory 11, and the brightness value that will read from video memory 11 (P1 '～P8 ') is stored in, and impact damper 22b '～22i ' (S4).

If brightness value (P0) is stored in impact damper 22a, (P1～P8) be stored in impact damper 22b～22i, then the first calculus of differences circuit 23a carries out calculus of differences 1, and operation result is sent to comparison/selection circuit 24 with brightness value.Particularly, the first calculus of differences circuit 23a obtains brightness value (P0) and brightness value (computing of the difference of the mean value of P1～P8) sends to comparison/selection circuit 24 with operation result.

In addition, if brightness value (P0) is stored in impact damper 22a, brightness value (P1 '～P8 ') is stored in impact damper 22b '～22i ', then the second calculus of differences circuit 23b carries out calculus of differences 2, and operation result is sent to comparison/selection circuit 24.Particularly, the second calculus of differences circuit 23b obtains the computing of difference of the mean value of brightness value (P0) and brightness value (P1 '～P8 '), and operation result is sent to comparison/selection circuit 24 (S5).In addition, hereinafter the operation result with calculus of differences 1 is called calculus of differences value 1, and the operation result of calculus of differences 2 is called calculus of differences value 2.

Receive the comparison/absolute value of 24 pairs of calculus of differences values 1 of selection circuit of calculus of differences value 1 and 2 and the size of the absolute value of calculus of differences value and compare (S6).Herein, under the situation of absolute value less than the absolute value of calculus of differences value 2 of calculus of differences value 1 (being "Yes" among the S6), comparison/selection circuit 24 selects calculus of differences value 1 as difference value (S7).

On the other hand, be that comparison/selection circuit 24 selects calculus of differences values 2 as difference value under the situation below the absolute value of calculus of differences value 1 at the absolute value of calculus of differences value 2.In addition,, under calculus of differences value 1 and 2 situations about equating, show the example of selecting calculus of differences value 2 herein, but under calculus of differences value 1 and 2 situations about equating, also can select any in calculus of differences value 1 and 2.

As mentioned above, the some selections in calculus of differences value 1 and 2 as difference value, and are sent to determining defects treatment circuit 30.Then, whether the 30 pairs of received difference values of determining defects treatment circuit that received difference value judge (S9) more than Th1 (bright spot detects and uses threshold value).Herein, be (to be "Yes" among the S9) under bright spot detects with the situation more than the threshold value at difference value, the decision content decision that the determining defects treatment circuit will be examined pixel is fleck defect pixel (S10).

On the other hand, detect with (being "No" among the S9) under the situation of threshold value less than bright spot at difference value, whether 30 pairs of difference values of determining defects treatment circuit judge (S11) below Th2 (stain detects and uses threshold value).Herein, be (to be "Yes" among the S11) under stain detects with the situation below the threshold value at difference value, the decision content decision that determining defects treatment circuit 30 will be examined pixel is black spot defect pixel (S12).Then, be (to be "No" among the S11) under stain detects with the situation more than the threshold value at difference value, the decision content decision that determining defects treatment circuit 30 will be examined pixel is normal pixel (S13).

As mentioned above, determining defects treatment circuit 30 will be examined the decision content decision of pixel as fleck defect pixel, black spot defect pixel or normal pixel, and the decision content that is determined is stored in output buffer 31 (S14).Then, view data write circuit 32 decision content that will leave output buffer 31 in is written to the specified address (S15) of second address control circuit 33 of video memory 11.

In addition, although not shown among Fig. 1, first address control circuit 20 is connected with second address control circuit 33.And also the address that is examined pixel that first address control circuit 20 is determined sends to second address control circuit 33.Thus, second address control circuit 33 can be specified the address that is examined pixel the target that writes as above-mentioned decision content.

In addition, second address control circuit 33 specified decision content write target after, to these information of first address control circuit 20 transmission.Thus, first address control circuit 20 recognizes the previous judgement that is examined pixel that determines has been finished, is transferred to the next one is examined pixel judges.That is, 20 pairs of vertical address counters of first address control circuit (Vcnt) add 1 (S16).

Then, whether 20 pairs of horizontal address counters of first address control circuit (Hcnt) judge (S17) at the operation of horizontal pixel count with interior.In addition, so-called operation of horizontal pixel count is meant image pixel quantity in the horizontal direction.That is, in S 17, the right-hand member that whether has arrived image is judged.Herein, the value of horizontal address counter be the operation of horizontal pixel count with interior situation under (being "Yes" among the S17), return S3, carry out defects detection and handle.In this case, be used to judge that the whether defective right side adjacent pixels that is examined pixel becomes the next one and is examined pixel before.

On the other hand, surpass under the situation of operation of horizontal pixel count (being "No" among the S17) at horizontal address counter, 20 pairs of vertical address counters of first address control circuit (Vcnt) add 1 (S18).

Then, whether the value of the vertical address counter after 20 pairs of increments of first address control circuit judges (S19) at vertical computing pixel count with interior.In addition, so-called vertical computing pixel count is meant image pixel quantity in vertical direction.That is, in S19, the lower end that whether has arrived image is judged.

Herein, the value of vertical address counter be vertical computing pixel count with interior situation under (be "Yes" among the S19), return S2, carry out the defects detection processing.In this case, the pixel that is used to judge whether defective below one row's who is examined pixel left end before being positioned at becomes the next one and is examined pixel.On the other hand, under the situation of the value bigger than vertical computing pixel count (being "No" among the S19) of vertical address counter, first address control circuit 20 is judged as that image is all pixels and has offered the defects detection processing, and the defects detection processing finishes.

(determining method of comparison other locations of pixels)

As mentioned above, the comparison other locations of pixels is according to being examined the predetermined decision of locations of pixels, will be examined the corresponding comparison other locations of pixels of locations of pixels and leave in the compared pixels determining positions table 25.Can not consider that also being examined the position of pixel in image decides the comparison other locations of pixels, change the comparison other locations of pixels but be examined the position of pixel in image, thereby can improve the accuracy of detection of defective by basis.

Herein, based on Fig. 6 to Fig. 8, illustrate according to being examined the example that the position of pixel in image changes the comparison other locations of pixels.Fig. 6 is that expression is taken display device P and the distortion that generates in the image that forms, and is used to set the figure of the relation between the piece of comparison other locations of pixels.

Yet, display frame at display device P is under the situation of large-scale display frame, when taking,, notified cylindrical shape distortion etc. has taken place in captured image because of the influence of the aberration that is subjected to lens etc. with 2 pairs of these display frames of camera head of area sensor type.Especially for camera heads such as the area sensor of FA purposes and TDI/ line sensors, because of the size of shooting element is bigger, therefore, the tendency that has the generating capacity of distortion to increase.In addition, under the situation of using wide-angle lens, the tendency of the generating capacity increase of distortion is arranged also.

Under the situation that the cylindrical shape distortion takes place, as shown in Figure 6, the part of the end of image becomes the picture shape that has circle.Thus, the image that has produced distortion in use carries out under the situation of defects detection, near the central portion of the image that does not produce distortion and produced near the end of image of distortion,, then may cause the accuracy of detection reduction of defective if set the comparison other locations of pixels identical.

For fear of such situation, need to change the comparison other locations of pixels according to being examined the position of pixel in image.For example, as shown in Figure 6, image is divided into 9, to every setting comparison other locations of pixels, thereby the accuracy of detection that can prevent defective reduces, and keeps the higher detection precision.

In example shown in Figure 6, image is divided into upper left bight (a), upper end (b), upper right bight (c), left part (d), central portion (e), right part (f), bight, lower-left (g), bottom (h), bight, bottom right (i) these nine.Then, carrying out as mentioned above under the situation of piecemeal, preparing in advance and the corresponding comparison position decision table of each piece.

At central portion (e),, therefore do not need to consider that the influence of being out of shape decides the comparison other locations of pixels owing to do not produce distortion.Thereby the comparison other locations of pixels of central portion (e) is as long as for example set like that shown in the example of Fig. 3.That is, the comparison position decision table of central portion (e) usefulness is to represent to become the table of the comparison other locations of pixels of configuration shown in Figure 3 with respect to being examined locations of pixels.

Then, in this case, first address control circuit 20 is when having determined to be examined locations of pixels, if the position that is determined is contained in central portion (e), then as long as use the comparison position decision table of central portion (e) usefulness to decide the comparison other pixel.Thus, will determine object pixel as a comparison with respect to the pixel that is examined locations of pixels and becomes position shown in Figure 3 relation.

On the other hand, in upper left bight (a), upper right bight (c), bight, lower-left (g), and bight, bottom right (i), owing to generate distortion, the influence that therefore needs to consider distortion decides the comparison other locations of pixels.For these pieces, as long as the comparison other locations of pixels is set at shown in the example of Fig. 7 for example like that.

Fig. 7 is the figure of the setting example of the comparison other locations of pixels in the bight of presentation video.In addition, in the figure, show pixel (P0), comparison other pixel 1 (P1～P4), comparison other pixel 2 (P1a～P4a), and comparison other pixel 3 (the position relation of P1b～P4b) of being examined.In addition, although not shown, each pixel is the interval cm=6 (with reference to Fig. 2) of (left and right directions) in the horizontal direction, and each pixel is at the interval cn=6 of vertical direction (above-below direction) (with reference to Fig. 2).

, in the example of Fig. 3, use 2 groups of (comparison other pixel 1 and 2) comparison other pixels herein, but in the example of Fig. 7, use 3 groups of (comparison other pixel 1～3) comparison other pixels.Under the situation of using 3 groups of comparison other pixels, from 3 groups of calculus of differences values, select the value of absolute value minimum, to being examined pixel inspection.In addition, in this example, the quantity of each group comparison other pixel is 4, and each group comparison other pixel count also can be 8 like that shown in the example of Fig. 3, also can be quantity in addition.

Thus, can suitably change defects detection handle in employed comparison other pixel the group number, and constitute comparison other pixel count of each group.In addition, the group number by increasing the comparison other pixel, and constitute comparison other pixel count of each group, thereby can improve defects detection result's reliability, but operand also increases simultaneously.Thereby, can according to the desired reliability of defect inspection, supervision time (computing circuit scale) of being allowed select the comparison other pixel the group number, and constitute comparison other pixel count of each group.

In the example of Fig. 7, in upper left bight (a), with the comparison other pixel be set in be positioned at the lower right that is examined pixel to the position.Its reason is, as shown in Figure 6, in upper left bight (a), upper left pixel, then its distortion is big more, bottom-right pixel, its distortion is more little.

Because same reason, in upper right bight (c), the comparison other pixel is set in the lower left that is examined pixel to the position, in bight, lower-left (g), the comparison other pixel is set in the upper right side that is examined pixel to the position, in bight, bottom right (i), the comparison other pixel is set in the upper left side that is examined pixel to the position.

In this case, upper left bight (a) with, upper right bight (c) with, bight, lower-left (g) with, and the comparison position decision table of bight, bottom right (i) usefulness represent to become (c) table of the comparison other locations of pixels of (g) configuration shown in (i) of Fig. 7 (a) with respect to being examined locations of pixels.

Then, in this case, first address control circuit 20 is when having determined to be examined locations of pixels, if the position that is determined is contained in upper left bight (a), upper right bight (c), bight, lower-left (g) or bight, bottom right (i), then as long as the comparison position decision table that uses this piece to use decides the comparison other pixel.Thus, will determine object pixel as a comparison with respect to the pixel that is examined locations of pixels and becomes position shown in Figure 7 relation.

Thus, upper left bight (a), upper right bight (c), bight, lower-left (g), and bight, bottom right (i) in, set the comparison other pixel, make it with respect to being examined the position that pixel is positioned at the less direction of distortion.In other words, the comparison other pixel is set in first address control circuit 20 outer edge (the pixel beyond the outer edge) avoiding being subjected to deformation effect bigger in the image.

Thus,,, can prevent that also the accuracy of detection of defective from descending, can keep the higher detection precision even therefore in image, produce under the situation of distortion owing to can reduce the influence of the distortion in the comparison other pixel.In addition, as long as set the comparison other locations of pixels, be not limited to illustrated embodiment in the mode that reduces the influence of being out of shape.

In addition, as shown in Figure 6, upper end (b), left part (d), right part (f), and bottom (h) in also produce distortion.Thereby, for these pieces, need also to consider that the influence of being out of shape decides the comparison other locations of pixels.For these pieces, as long as the comparison other locations of pixels is set at shown in the example of Fig. 8 for example like that.

Fig. 8 be presentation video upper end (b), left part (d), right part (f), and bottom (h) in the figure of setting example of comparison other locations of pixels.In addition, in the figure, show pixel (P0), comparison other pixel 1 (P1～P4), comparison other pixel 2 (P1a～P4a), and comparison other pixel 3 (the position relation of P1b～P4b) of being examined.Identical with the example of Fig. 7, can suitably change defects detection handle in employed comparison other pixel the group number, and constitute comparison other pixel count of each group.In addition, although not shown, each pixel is the interval cm=6 (with reference to Fig. 2) of (left and right directions) in the horizontal direction, and each pixel is at the interval cn=6 of vertical direction (above-below direction) (with reference to Fig. 2).

As shown in Figure 8, in upper end (b), the comparison other pixel is set in the position of the below that is examined pixel.Its reason is, as shown in Figure 6, in upper end (a), deforms in the pixel of the upside of piece, and deforms hardly in the pixel of downside.

Because same reason, in left part (d), the comparison other pixel is set in right-hand position that is examined pixel, in right part (f), the comparison other pixel is set in the position of the left that is examined pixel, in bottom (h), the comparison other pixel is set in the position of the top that is examined pixel.

In this case, upper end (b) with, left part (d) with, right part (f) with, and the comparison position decision table of bottom (h) usefulness represent to become (d) table of the comparison other locations of pixels of (f) configuration shown in (h) of Fig. 8 (b) with respect to being examined locations of pixels.

And, in this case, first address control circuit 20 is when having determined to be examined locations of pixels, if the position that is determined is contained in upper end (b), left part (d), right part (f) or bottom (h) are then as long as the comparison position decision table that uses this piece to use decides the comparison other pixel.Thus, will determine object pixel as a comparison with respect to the pixel that is examined locations of pixels and becomes position shown in Figure 8 relation.

Thus, upper end (b), left part (d), right part (f), and bottom (h) in, set the comparison other pixel, make it with respect to being examined the position that pixel is positioned at the less direction of distortion.In other words, the comparison other pixel is set in first address control circuit 20 outer edge (the pixel beyond the outer edge) avoiding being subjected to deformation effect bigger in the image.

(being examined the correction of reading in the position of pixel and comparison other pixel)

As mentioned above, checking that object is under the larger-size situation of display device P, sometimes produce distortion in the image of this display device P being taken and obtaining, the image that has produced distortion in use carries out under the situation of defects detection, and to change the comparison other locations of pixels be effective according to being examined locations of pixels.

, in image, produced under the situation of distortion herein, according to being examined the position of pixel in image, proofreading and correct the position of reading in that is examined pixel and comparison other pixel, thereby can further reduce the influence of distortion.Hereinafter, based on Fig. 9, illustrate according to being examined the position of pixel in image and proofread and correct the method for reading in the position that is examined pixel and comparison other pixel.

Fig. 9 is the figure of relation of the spacing of the pixel in the image that generates with this position is taken of explanation position when the 2 couples of display device P of camera with TDI/ line sensor type take, on the display device P.In addition, suppose following situation in the figure: promptly, relatively move on (direction shown in the arrow B) in the horizontal direction, thereby the whole face of the picture display face of display device P is taken by camera head 2 and the display device P that makes TDI/ line sensor type.

Thus, under the situation that camera head 2 and display device P are relatively moved along the direction shown in the arrow B, Yi Bian camera head 2 keeps the row of imaging apparatus and arrow B perpendicular all the time, Yi Bian take.Because camera head 2 general most shootings that are used for large-scale display device P of TDI/ line sensor type, therefore the imaging apparatus number that is comprised in the row also can reach thousands of.In addition, in order further to enlarge image pickup scope, also have under a lot of situations and use wide-angle lens.

In this case, the shooting area of each imaging apparatus of camera head 2 is according to the distance of the position that becomes reference object of display device P and this imaging apparatus and different.Promptly, as shown in Figure 9, than the position of taking down with the shortest state of the distance of camera head 2 and display device P (A), bigger with the shooting area of each imaging apparatus at the position (C) of shooting under the longest state of the distance of camera head 2 and display device P.In other words, higher, lower with the shooting density of the part of the distance of camera head 2 end far away with the shooting density of the middle body of the close together of camera head 2.

Therefore, than near the position (A) the central portion of image, narrower near position (B) pixel separation in vertical direction of the end of image, pixel separation in vertical direction is narrower at the position nearer from the end (C).

For example, in illustrated embodiment, pixel A 1 that is comprised in the image that obtains in that position (A) taken and A2 in the horizontal direction be spaced apart cm, in vertical direction be spaced apart cn.Corresponding, position (C) taken and the pixel C1 that comprised in the image that obtains is identical with position (A) with C2 interval cm in the horizontal direction, but interval in vertical direction become cn ' (cn '＜cn).Like this, the end of the image that distance approaching more and camera head 2 is far away, then pixel separation in vertical direction is narrow more.

Thereby, just do not read in brightness value if do not consider the difference of above-mentioned pixel separation from image, position after the skew then can take place from the position that should read the script brightness value read brightness value, carry out the detection of defective based on this brightness value, thereby may cause the reduction of defects detection precision.

For fear of above-mentioned situation, can consider for example to proofread and correct to make the offset of reading in that is examined pixel and comparison other pixel according to the position on the image.Particularly, first address control circuit 20 uses compared pixels determining positions table 25 to decide the position of reading in that is examined pixel and comparison other pixel, afterwards, use position on the image, and the correcting value corresponding to this position between set up the pixel separation decision table 26 of corresponding relation, proofread and correct the position of reading in of above-mentioned decision.

Thus, even under the different situation of the image spacing of the central portion of the image that causes being used for defects detection because of the aberration of lens or distortion etc. and end, also can suitably proofread and correct read-out position to the brightness value of this image, realize high-quality comparison operation processing, can detect defective accurately.

In addition, also can make the correcting value of the read-out position of brightness value take place to change continuously according to the distance (distance on the vertical direction) of taking the position (A) that obtains from the shortest state of camera head 2 and the distance of display device P down, also can be predetermined correcting value according to each piece according to the distance of (A) is a plurality of with image segmentation from the position.

Embodiment 2

Be that following example is illustrated in the above-described embodiment: promptly, respectively to the comparison other pixel of two groups (or more than 3 groups) be examined pixel and carry out calculus of differences, from the calculus of differences result, use the calculus of differences result of absolute value minimum, carry out the judgement of defects detection.According to above structure,, therefore,, also can suppress the generation of false defect even comprise the pixel that brightness value is an exceptional value in the comparison other pixel owing to from a plurality of calculus of differences results, use the calculus of differences result of the most difficult generation false defect.

Yet, in the comparison other pixel, comprise under the situation of the pixel that brightness value is an exceptional value (pixel of the brightness value of the defective locations of reflection display device P), also can think and in the comparison operation result, reflect exceptional value and cause the defects detection precision to reduce.

Therefore, in the defect detecting device 1 of present embodiment, under the situation of the brightness value that predicts the comparison other pixel when being unusual, this comparison other pixel is changed into other pixel.Thus, can prevent from exceptional value is reflected among the comparison operation result, can further improve the reliability of defects detection.

(briefing of defect inspection method)

Based on Figure 10, the briefing of the defect inspection method that defect detecting device 1 ' carried out of present embodiment is described herein.Figure 10 is the concise and to the point figure of the defect inspection method of explanation present embodiment.In addition, in Figure 10, represent to be examined pixel, represent comparison other pixel 1, represent comparison other pixel 2, represent comparison other pixel 3 with P1b～P8b with P1a～P8a with P1～P8 with P0.

Like this,, use 3 groups of comparison other pixels 1～3 herein.And, in the stage before carrying out calculus of differences, from the comparison other pixel, extract and be predicted as the pixel that brightness value is an exceptional value.In addition, in image, be that the state that the position of exceptional value can be read with defect detecting device 1 ' is stored in advance for being predicted as brightness value.

Then, the comparison other pixel and the comparison other pixel (brightness value is not the comparison other pixel of exceptional value) in addition that are extracted are replaced, use the comparison other pixel after replacing to carry out calculus of differences.Thus, can prevent from exceptional value is reflected among the comparison operation result, can further improve the reliability of defects detection.

For example, in example shown in Figure 10, with the configuration settings comparison other pixel 1 identical (P1～P8), and comparison other pixel 2 (P1a～P8a), and set comparison other pixel 3 (P1b～P8b) with the example of Fig. 3.Setting comparison other pixel 3 (P1b～P8b), make the become P1b adjacent with the left side of P1a, adjacent with the upside of the P2a P2b that becomes, adjacent with the upside of the P3a P3b that becomes, the lower left of P4a becomes P4b, and the upper right side of P5a becomes P5b, adjacent with the below of the P6a P6b that becomes, adjacent with the downside of the P7a P7b that becomes, adjacent with the right side of the P8a P8b that becomes.

And, as shown in figure 10, by P3, P5, and the straight line of P8 on line defect takes place.That is, P3, the P5 that herein supposes in comparison other pixel 1, to be comprised, and the brightness value of P8 undesired.In this case, if ((P1a～P8a) compares computing, is then using comparison other pixel 1 (to reflect among the comparison operation result of P1～P8) that exceptional value is P3, P5, and the brightness value of P8 for P1～P8) and comparison other pixel 2 to use comparison other pixel 1.

Therefore, as shown in figure 10,, replace with P3b, P5b, the P8b of P3a, P5a, P8a or the comparison other pixel 3 of comparison other pixel 2 for P3, the P5 of comparison other pixel 1, and P8.Thus, can prevent to reflect among the comparison operation result that exceptional value is P3, P5, the brightness value that reaches P8.

In addition, in example shown in Figure 10, ((P1b～P8b) is the object pixel 1 (candidate of the replacement of P1～P8), but be not limited to this example as a comparison for P1a～P8a) or comparison other pixel 3 with comparison other pixel 2.The candidate of replacing is so long as be contemplated for the pixel (pixel that brightness value is stored as exceptional value) of the normal position of brightness value and get final product.

In addition, in example shown in Figure 10, show the example of 1 group of 3 groups of comparison other pixel 1～3 that constitute by 8 comparison other pixels, but as shown in figure 11, comparison other pixel of each group also can be 4.Figure 11 shows following example: promptly, under the situation of using 1 group of 3 groups of comparison other pixel 1～3 that comprise 4 comparison other pixels, the comparison other pixel of defective locations is changed into the comparison other pixel of the position that does not have defective.In Figure 11, be from the comparison other pixel of Figure 10, removed P2, P4, P5, P7, P2a, P4a, P5a, P7a, P2b, P4b, P5b, and P7b after state.

(detailed structure of defect detecting device 1 ')

Then, based on Figure 12, the detailed structure of the defect detecting device 1 ' of carrying out above-mentioned defect inspection method is described.Figure 12 is the block diagram of major part structure of the defect detecting device 1 ' of expression present embodiment.In addition, for the structure identical with the defect detecting device 1 of above-mentioned embodiment shown in Figure 1, additional phase with reference to label, omit its explanation.

Defect detecting device 1 ' has identical structure with defect detecting device 1 shown in Figure 1 except replace difference value calculating part 12 this point with difference value calculating part 12 '.In addition, difference value calculating part 12 ' also comprises defective locations storer (defective locations storage part) 27 and selects circuit (the comparison other pixel changes the unit) 28 except the structure that comprises difference value calculating part 12 and comprised.

Defective locations storer 27 is that the display device P that becomes the defects detection object is taken and the storer that deposits the position of defective in the image that obtains.In the defective locations storer 27, can be stored in defects detection handle before detected in advance defective locations, also can leave in defects detection handle in detected defective locations.In addition, will narrate the processing that detected defective locations in the defects detection processing is stored in defective locations storer 27 afterwards.

Select circuit 28 to receive the comparison other locations of pixels, received position is judged with whether the defective locations in leaving defective locations storer 27 in is consistent from first address control circuit 20.Then, select the pixel replacement of circuit 28 usefulness defective locations position in addition and the comparison other pixel of the corresponding to position of defective locations.In addition, for becoming the replacement object pixels, in the pixel that can become the comparison other pixel, promptly the brightness value of this pixel is under the situation (not having the situation of defective with the position of the corresponding display device P of this pixel) of normal value, so long as get final product with the pixel that is examined pixel and becomes in theory the same brightness value of normal value.

(flow process that the replacement of comparison other pixel is handled)

Also can for example realize as shown in Figure 13 will be with the comparison other pixel replacement on the defective locations consistent location position beyond the defective locations pixel, decide the processing of comparison other pixel.Figure 13 is the process flow diagram of an example of the processing of expression decision comparison other pixel.

At first, select circuit 28 to read the defective locations (S30) that leaves in the defective locations storer 27.Then, select circuit 28 from first address control circuit 20 read-around ratio than the position (S31) of the P1a '～P8a ' of the position of the P1～P8 of object pixel 1 and comparison other pixel 2.

Then, select the P1～P8 of the comparison other pixel 1 that 28 pairs in circuit reads in S31 the position, judge (S32) with the defective locations of reading is whether consistent in S30., under being judged as inconsistent situation, (be "No" among the S32) herein, select circuit 28 indications first address control circuit 20 to read in the brightness value of the position of P1～P8.

Then, first address control circuit 20 that receives indication reads in view data with the brightness value of P1～P8 position and reads in circuit 21.Thus, the brightness value of the position of P1～P8 is stored in impact damper 22b～22i, outputs to the first calculus of differences circuit 23a (S35).

On the other hand, under being judged as consistent situation, (be "Yes" among the S32), select circuit 28 indications first address control circuit 20, the brightness value with the defective locations consistent location among P1～P8 is replaced with defective locations brightness value (S33) in addition.

Then, first address control circuit 20 that receives indication is with the reading in the position of P1～P8, replace with other position with the defective locations consistent location.Thus, view data is read in the position that circuit 21 reads in brightness value and is changed, and the brightness value after replacing is stored in impact damper 22b～22i, outputs to the first calculus of differences circuit 23a (S34).

For example, in the example of Figure 10, P3, P5, and P8 consistent with defective locations.Thereby, in this case,, P5 and P8 are also carried out identical replacement with the position of reading in that the position replaces with P3a or P3b of reading in of P3.Herein, (P1b～P8b) be made as under the situation of replacing special use has deposited P1, P2, P3b, P4, P5b, P6, P7, P8b respectively in impact damper 22b～22i with comparison other pixel 3 in hypothesis.In addition, when in P3b, P5b, P8b, comprising with the corresponding to position of defective locations, further with other positions (for example, P3a, P5a P8a) is set at and reads in the position.

Thus, if to first calculus of differences circuit 23a output brightness value, then select the P1 '～P8 ' of the comparison other pixel 1 that 28 pairs in circuit reads in S31 the position, judge (S36) with the defective locations of reading is whether consistent in S30., under being judged as inconsistent situation, (be "No" among the S36) herein, select circuit 28 indications first address control circuit 20 to read in the brightness value of the position of P1 '～P8 '.

Then, first address control circuit 20 that receives indication reads in view data with the brightness value of P1 '～P8 ' position and reads in circuit 21.Thus, the brightness value of the position of P1 '～P8 ' is stored in impact damper 22b '～22i ', outputs to the second calculus of differences circuit 23b (S39).

On the other hand, under being judged as consistent situation, (be "Yes" among the S36), select circuit 28 indications first address control circuit 20, the brightness value with the defective locations consistent location among P1 '～P8 ' is replaced with defective locations brightness value (S37) in addition.

Then, first address control circuit 20 that receives indication is with the reading in the position of P1 '～P8 ', replace with other position with the defective locations consistent location.Thus, view data reads the position that circuit 21 reads in brightness value and changes, and the brightness value after replacing is stored in impact damper 22b '～22i ', outputs to the second calculus of differences circuit 23b (S38).

By carrying out above-mentioned processing,, therefore can prevent from the comparison operation result, to reflect exceptional value owing to can be only come constituent ratio than object pixel by (brightness value is a normal value) pixel not at defective locations.In addition, also can carry out the processing of S32～S35 and the processing of S36～S39 simultaneously.

In addition, select circuit 28 owing to comprise, as mentioned above, acquisition prevents to reflect the effect of the brightness value of improper pixel in the comparison operation result, in addition, also acquisition can use the group of the brightness value of selecting from impact damper 22a～22i and 22a '～22i ' arbitrarily to compare the effect of computing.That is, select circuit 28, then can increase the number of combinations of the comparison other pixel of the object that becomes comparison operation, therefore can improve versatility owing to comprise.

For example, also can carry out following processing: promptly, 4 brightness values to from impact damper 22a～22i, selecting, output to the first calculus of differences circuit 23a, 8 remaining brightness values are outputed to the second calculus of differences circuit 23b etc. with four brightness values from impact damper 22a '～22i ', selecting.Thus, by changing the combination of brightness value,, therefore repeatedly check, thereby can further improve the defects detection precision with different combinations because the calculus of differences value that is calculated also becomes different values.

(example of the detection method of stored defective locations in the defective locations storer 27)

Under obtaining the situation that leaves the defective locations in the defective locations storer 27 in advance, handle (with reference to Fig. 5) before carrying out above-mentioned defects detection, the image that need obtain, detect the processing of defective from display device P is taken.This processing is to want to detect point defect from image and line defect gets final product, and also can use always employed conventional method.

Based on Figure 14 and Figure 15, the example of the detection method that leaves the defective locations in the defective locations storer 27 in is described herein.Figure 14 is the figure of an example of the detection method of expression defective locations, is the figure that expression display device P reaches the accumulated value of the brightness value on the horizontal direction in vertical direction.In Figure 14, represent that with ax the accumulated value of each position brightness value in vertical direction of the horizontal direction of display device P distributes, represent that with ay the accumulated value of each position brightness value in the horizontal direction of the vertical direction of display device P distributes.

As shown in figure 14, suppose in display device P, to take place line defect L1 herein.Under the situation that line defect takes place, the brightness value of the pixel of line defect part becomes exceptional value.Therefore, at the position that line defect takes place, vertically or under horizontal direction the situation that brightness value is accumulated, its accumulated value also becomes the value that is different from normal value.More specifically, the position of line defect takes place in vertical direction, the accumulated value that comprises the brightness value on the vertical direction at this position becomes the value that is different from normal value, the position of line defect takes place in the horizontal direction, and the accumulated value that comprises the brightness value on the horizontal direction at this position becomes the value that is different from normal value.

In example shown in Figure 14, owing to from the pixel of the 4th row on a left side, line defect L1 takes place, therefore, become the value that is different from normal value at accumulated value with brightness value on the vertical direction of the corresponding position of pixel of a left side the 4th row.In Figure 14, represent the normal value of the accumulated value of brightness value in vertical direction with Nx.In distributing with the corresponding accumulated value in the position that line defect L1 takes place, like that, the accumulated value of brightness value surpasses Nx, or shown in a2, the accumulated value of brightness value is littler than Nx shown in the a1 as shown.

Therefore, based on accumulated value distribution ax and ay, can determine the happening part of the display defect of display device P.In addition, surpass under the situation of Nx, can be judged as the bright line defective has taken place, under the situation littler, can be judged as the black line defective has taken place than Nx at the accumulated value of brightness value.

Figure 15 is identical with Figure 14, also is the figure of an example of the detection method of expression defective locations, is the figure that expression display device P reaches the accumulated value of the brightness value on the horizontal direction in vertical direction.In Figure 15, represent that with bx the accumulated value of each position brightness value in vertical direction of the horizontal direction of display device P distributes, represent that with by the accumulated value of each position brightness value in the horizontal direction of the vertical direction of display device P distributes.

As shown in figure 15, suppose the line defect L2 of occurred level direction in display device P herein.Therefore, reflect the influence of L2 among the accumulated value distribution bx of brightness value in vertical direction.That is, with the brightness value of the corresponding position of line defect L2 of accumulated value distribution bx or than normal value Ny little (b1), or than normal value Ny big (b2).

Thus, the accumulated value that vertical direction and the horizontal direction of display device P are obtained brightness value, thus can detect the display defect that occurs in display device P, and determine the position of this display defect.Then, the position of obtaining as mentioned above is stored in defective locations storer 27, thereby can from the comparison other pixel, removes the pixel of defective locations.

In addition, the unit that utilizes said method to detect defective locations can be contained in defect detecting device 1 ', also can utilize said method to detect defective locations, and detected result is sent to defective locations storer 27 by the device of the outside of defect detecting device 1 '.In addition, the detection method of defective locations is not limited to above example.

(defects detection result's feedback).

, as mentioned above, carry out under the situation of defects detection herein, have elongated problem of processing time in the pre-service of handling as defects detection.Therefore, in defect detecting device 1 ' shown in Figure 12, handle, thereby also can from the comparison other pixel, remove the pixel of defective locations by the setting that the defects detection result is fed back to the comparison other pixel.

That is, as shown in figure 12, in defect detecting device 1 ', the result that determining defects treatment circuit 30 is carried out determining defects outputs to output buffer 31, and also outputs to defective locations storer 27.Thus, because of defective locations leaves in the defective locations storer 27, therefore select circuit 28 can from the comparison other pixel, remove the pixel of the position of determining defects treatment circuit 30 detected defectives.

That is,, can not carry out the pre-service of defects detection, just from the comparison other pixel, remove the pixel of defective locations according to said structure.Therefore, can not increase defects detection and handle the needed time, just improve the precision of defects detection, and significantly reduce the generating capacity of false defect.

(variation that comparison operation is handled)

In above-mentioned example, illustrated that the arithmetic mean (addition is average) of the brightness value by calculating the comparison other pixel is worth and is examined the difference of the brightness value of pixel, compares the example of calculation process.Under the situation of using arithmetic mean, because calculation process is simple, so easy high speed is handled in comparison operation.In addition, under the situation of using arithmetic mean,, can easily improve the result's of comparison operation processing reliability by increasing the quantity of comparison other pixel.

Yet the comparison operation processing is not limited to the arithmetic mean of the brightness value that compares object pixel is carried out Calculation Method with the difference that is examined the brightness value of pixel.For example, comparison operation is handled also and can be calculated the arithmetic mean of the brightness value of the maximal value of removing brightness value of object pixel relatively and/or minimum value and the difference that is examined the brightness value of pixel.Thus, can get rid of because of noise etc. for example takes place becomes the influence of the brightness value of exceptional value, thereby can improve the result's that comparison operation handles reliability.

In addition, also can obtain the deviate of the brightness value of comparison other pixel, select to be used for the pixel that comparison operation is handled based on the deviate of being obtained.That is, the position that defective does not take place of general display device P (position that shows with normal brightness value) is more than the position of generation defective (position that shows with the brightness value that is different from the normal brightness value).Therefore, setting under the situation of a plurality of comparison other pixels, the possibility that the pixel that becomes normal value is Duoed than the pixel that becomes exceptional value is higher.

Thereby, can think that under the less situation of deviate, the brightness value of this pixel is that the possibility of normal value is higher, under the bigger situation of deviate, the brightness value of this pixel is that the possibility of exceptional value is higher.Therefore, the deviate of the brightness value by obtaining the comparison other pixel is got rid of the deviate pixel of being obtained bigger than the value that is predetermined, and is the influence of the higher pixel comparison of the possibility of exceptional value than the result of calculation process thereby can reduce brightness value.

And, also the brightness value based on a plurality of comparison other pixels can be utilized linear interpolation and the brightness value that is examined locations of pixels obtained and the difference that is examined the brightness value of pixel are used as the calculus of differences value.In this case, eliminate dark variation of the system of Himdu logic and the inclination of the brightness value that produces, can improve the reliability that comparison operation is handled.

For example, the comparison other location of pixels in the example of Fig. 8 (d), the dark influence that changes of the system of Himdu logic, the brightness value almost pixel with the left side of this figure is the same low.For example, the situation that consider that brightness value as P0 is 60, the brightness value of P2 is 70, the brightness value of P4 is 80 brightness value run-off the straight.In addition, the brightness value of establishing P0 is normal (display device P with the corresponding position of P0 defective does not take place).

In this case, the arithmetic mean of the brightness value of the brightness value of P2 and P4 becomes (70+80)/2=75.Thereby under the situation of the difference of the arithmetic mean of the brightness value that obtains the brightness value that is examined pixel and comparison other pixel, the calculus of differences value is (60-75)=-15 (because be negative value, being black spot defect therefore).Because of the calculus of differences value is not zero, in this case, false defect may take place.

On the other hand, utilize linear interpolation based on the brightness value of the brightness value of P2 and P4 and the brightness value of the position of the P0 that obtains becomes (2 * 70)-80=60.Thereby under the situation of carrying out linear interpolation, the calculus of differences value becomes (60-60)=0.Because of the calculus of differences value is zero, in this case, false defect can not take place.

As mentioned above,, the dark variation of the system of Himdu logic can be eliminated and the inclination of the brightness value that causes, the reliability that comparison operation is handled can be improved by using linear interpolation.Particularly in that being set at, the comparison other locations of pixels leaves under the situation that is examined locations of pixels, or under being examined the situation that pixel and comparison other pixel packets be contained in bight or end (zone beyond the central portion in the example of Fig. 6), because the influence that light and shade changes becomes greatly, therefore preferably use linear interpolation.

In addition, also can use arithmetic mean carry out calculus of differences, use linear interpolation to carry out calculus of differences etc., suitably make up above-mentioned comparison operation and handle and carry out defects detection and handle at position in addition at the less central portion of the influence that changed by light and shade.In addition, as shown in figure 16, the dark influence that changes of the system of Himdu logic, the brightness value of the central portion of image becomes different values with the brightness value of periphery.Therefore, also can carry out the correction (standardization) of brightness value, use the brightness value after proofreading and correct to carry out calculus of differences according to the position in the image.

The invention is not restricted to the respective embodiments described above, can carry out all changes in the scope shown in claims, the embodiment that obtains for the technological means that discloses respectively in the different embodiments of appropriate combination is also contained in the technical scope of the present invention.

At last, each frame, particularly difference value calculating part and determining defects portion that defect detecting device 1,1 ' is comprised can adopt hardware logic to constitute, and also can come to realize by software by such CPU of use as follows.

That is, defect detecting device 1,1 ' possesses: CPU (the central processing unit: central processing unit) that carries out the control program instruction that realizes each function; Deposit ROM (the read only memory: ROM (read-only memory)) of described program; Launch RAM (the random access memory: random access memory) of described program; And deposit memory storages such as described program and various memory of data (recording medium) etc.Then, in recording medium, write down the software of realizing above-mentioned functions, be the program code (executable program, intermediate code program, source program etc.) of defect detecting device 1,1 ' control program with the embodied on computer readable form, this recording medium is offered above-mentioned defect detecting device 1,1 ', also carried out by the program code that writes down in its computing machine (or CPU, MPU) read-out recording medium, also can be realized purpose of the present invention thus.

That is, execution can be used for to check on the object be examined the corresponding position of pixel whether the processing that defectiveness is judged program code or carry out needed data etc. as the defects detection program.Then, carry out this defects detection program, also can reach purpose of the present invention by making computing machine.

As aforementioned recording medium, for example can be with semiconductor memory class of the card class of the band class of tape or tape etc., the dish class that comprises CDs such as disks such as floppy disk (floppy (registered trademark) disc)/hard disk and CD-ROM/MO/MD/DVD/CD-R, IC-card (comprising storage card)/light-card etc. or mask rom/EPROM/EEPROM/ flash rom etc. etc.

In addition, defect detecting device 1,1 ' also can adopt the structure that can be connected with communication network, supplies with described program code by communication network.As this communication network, be not particularly limited, for example can utilize internet, Intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual individual net (virtual private network), telephone wire road network, mobile radio communication, satellite communication link etc.In addition, as the transmission medium that constitutes communication network, be not particularly limited, wired mode of for example available IEEE1394, USB, power line carrier, catv line, telephone line, adsl line etc., wireless mode such as the such infrared ray of also available IrDA or telepilot, bluetooth (Bluetooth (registered trademark)), 802.11 wireless, HDR, mobile telephone network, satellite circuit, ground wave digital network.In addition, the present invention can realize that also the mode said procedure code, that embed the computer data signal in the carrier wave realizes in the mode by electric transmission.

In addition, embodiment or embodiment that the item of the mode that is used for carrying out an invention is finished are in order to illustrate technology contents of the present invention, be not interpreted as with not answering narrow sense and be only limited to such object lesson, can spirit of the present invention and below in the scope of claims of being put down in writing, carry out variously being implemented after changing.

Industrial practicality

According to the defect detecting device of the invention described above, the image based on obtaining checking object to take when the defective to this inspection object detects, can suppress the generation of false defect. This defect detecting device is particularly suitable for point defect, the line defect of detection display device, but so long as have repeat patterns, can be applicable to then that detection checks the defective of object arbitrarily.

Claims

1. a defect detecting device is characterized in that,

Brightness value based on the brightness value that is examined pixel and comparison other pixel; Defective to described inspection object detects; The described brightness value that is examined pixel is from the image that obtains checking object to take, namely has the image of the pattern that brightness value repeats with certain cycle and extract; Described comparison other pixel is to select from leaving described being examined the pixel pixel in described certain cycle; The brightness value of described comparison other pixel extracts from described image

Comprise a plurality of described comparison other pixels and mutually different a plurality of comparison other pixel group and described to be examined pixel corresponding, comprising:

The index computing unit, this index computing unit is for each comparison other pixel group of described a plurality of comparison other pixel groups, calculate each the comparison other pixel that is comprised in the described comparison other pixel group of expression brightness value, with the index of the size of the deviation of the described brightness value that is examined pixel;

Index in the index that index selected cell, this index selected cell calculate described index computing unit, the absolute value minimum is selected as the defects detection index; And

The determining defects unit, this determining defects unit is based on the magnitude relationship of the selected defects detection of described index selected cell with index and the threshold value that is predetermined, comes being examined the corresponding position of pixel whether defectiveness is judged with described described inspection object.

2. defect detecting device as claimed in claim 1 is characterized in that,

Comprise comparison other pixel setup unit, described comparison other pixel is set in the outer edge that this comparison other pixel setup unit is avoided described image.

3. defect detecting device as claimed in claim 1 or 2 is characterized in that, comprising:

The defective locations storage part is deposited the defective locations data of the position on expression and the corresponding described image of defective locations of described inspection object in this defective locations storage part; And

The comparison other pixel changes the unit, this comparison other pixel changes unit under described comparison other pixel and the corresponding to situation in position shown in the defective locations data that leave in the described defective locations storage part, this comparison other pixel is changed into the pixel of the position different with the position shown in the described defective locations data.

4. defect detecting device as claimed in claim 3 is characterized in that,

When described determining defects unit will be judged to be defectiveness in the described inspection object be examined the position of pixel on described image, as described defective locations deposit data to the defective locations storage part,

Described comparison other pixel changes the unit and uses described determining defects unit to leave the defective locations data of described defective locations storage part in, changes the comparison other pixel.

5. as each described defect detecting device of claim 1 to 4, it is characterized in that,

Comprise the extracting position correcting unit, this extracting position correcting unit in the described image, when taking and in pixel and the comparison other pixel at least one of being examined of closing on different position, position most of the immediate position of camera head, this extracting position that is examined at least one brightness value of pixel and comparison other pixel is proofreaied and correct, make it near the described position of closing on most, and make this correcting value close on the position at position most and become big along with becoming away from described.

6. as each described defect detecting device of claim 1 to 5, it is characterized in that,

As described index, described index computing unit calculates:

The mean value of the brightness value of each comparison other pixel that described comparison other pixel group is comprised is poor with the brightness value that is examined pixel;

Or from described comparison other pixel group, removed the remaining comparison other pixel at least one side back in the comparison other pixel of the comparison other pixel of brightness value maximum in this comparison other pixel group or brightness value minimum brightness value mean value and be examined brightness value poor of pixel;

Or the mean value of deviate in the comparison other pixel that is comprised in the described comparison other pixel group, that removed brightness value brightness value of remaining comparison other pixel after and be examined brightness value poor of pixel than the big comparison other pixel of predetermined value;

Or the brightness value of the comparison other pixel that described comparison other pixel group comprised carried out linear interpolation and described brightness value poor that is examined the brightness value of locations of pixels and is examined pixel obtained.

7. a defect inspection method is characterized in that,

This defect inspection method is carried out by following defect detecting device, described defect detecting device is based on the brightness value of brightness value that is examined pixel and comparison other pixel, defective to described inspection object detects, the described brightness value that is examined pixel is the image that obtains to checking object to take, promptly have and extract in the image of the pattern that brightness value repeats with certain cycle, described comparison other pixel is to select from leaving described being examined the pixel pixel in described certain cycle, the brightness value of described comparison other pixel extracts from described image

The index calculation procedure, this index calculation procedure is for each comparison other pixel group of described a plurality of comparison other pixel groups, calculate each the comparison other pixel that is comprised in the described comparison other pixel group of expression brightness value, with the index of the size of the deviation of the described brightness value that is examined pixel;

Index is selected step, and this index selects index in the index that step calculates described index calculation procedure, the absolute value minimum to select as the defects detection index; And

The determining defects step, this determining defects step is selected the magnitude relationship of the selected defects detection of step with index and the threshold value that is predetermined based on described index, comes being examined the corresponding position of pixel whether defectiveness is judged with described described inspection object.

8. defects detection program,

Be used for making each described defect detecting device of claim 1 to 6 to move, it is characterized in that,

Be used to make computing machine to play function as described each unit.

9. the recording medium of an embodied on computer readable is characterized in that,

Record the described defects detection program of claim 8.